Have you ever agreed to something and then spent the whole night regretting it?
Not because the task was hard — but because you simply didn't want to do it. Yet the moment the other person asked, your mouth moved faster than your brain: "Sure, no problem." Then you got home, sat down at your dressing table, and felt as though a little more of you had been scooped out.
You know where the problem lies. You know the phrase "set a boundary". But every time you think about saying no, your mind instantly conjures the other person's disappointed face, the relationship that might fracture, and a voice that won't go away: "Am I being too selfish?"
This article isn't here to teach you to become cold. Quite the opposite — psychological research tells us that people who know how to set boundaries actually have healthier, longer-lasting relationships. Because a boundary was never a wall. It's a door: you decide when it opens and when it closes.
Why some people just can't say "no"
Before we talk about how to set boundaries, there's one thing to understand first: being unable to say "no" is often not a sign of a weak personality, but a deep-seated survival strategy.
The psychotherapist Pete Walker proposed the concept of the "fawn response" — and like the more familiar fight, flight and freeze reactions, it is an automatic response to threat. The difference is that the "threat" behind the fawn response isn't a wild beast, but a sense of insecurity within a relationship. When someone learns from childhood that "I'm only safe when I keep the other person happy", they develop an exquisitely sensitive radar — constantly scanning for other people's needs, constantly adjusting themselves to accommodate.
This isn't a choice. It's instinct.
Research on attachment theory points in a similar direction. People with an anxious attachment style are especially sensitive to distance within a relationship. When they feel a boundary has been crossed, they experience intense emotional reactions — anger, hurt, confusion. But because they fear abandonment, they often forgive the other person's overstepping very quickly, and may even rationalise it (Front. Psychol., 2015). People with an avoidant attachment style go to the other extreme: they are highly alert to anything that intrudes on their space, and tend to use emotional distance to "protect" themselves.
Both types are wrestling with the same issue — boundaries. They simply do it in opposite ways: one has torn the door off, the other has welded it shut.
What is a boundary, really? (Not what you think)
Many people assume a boundary just means "rejecting others". But that understanding is far too narrow.
The clinical psychologist Henry Cloud offered a very intuitive definition: a boundary defines the territory of "me" — what is my responsibility and what isn't; what I can accept and what I can't. It tells me where I end and another person begins.
The key to this definition isn't "rejection" — it's clarity.
When you know what is yours and what isn't, you actually become more free — because you're no longer carrying weight that was never yours to begin with. You don't need to be responsible for other people's emotions, and you don't need to trade your own needs for their approval.
Boundaries exist on every level of life. Some are easy to recognise; others are buried deep.
Physical boundaries are the most direct — your bodily space, your personal belongings, your comfort level with being touched. In Hong Kong's cramped living conditions, blurred physical boundaries are almost the norm. People living in subdivided flats, or sharing a room with family, struggle to hold on to even the most basic physical space. But even when space is limited, you still have the right to decide who can touch you, and when.
Emotional boundaries are subtler. They determine how much of other people's emotions you're willing to carry. Have you ever had a friend ring you up to vent, talk for two hours, and after hanging up you felt more exhausted than they did? That's the feeling of an emotional boundary being overrun. Your empathy is a capacity — but it isn't an infinite resource.
Time boundaries are especially easy to overlook in Hong Kong's overtime culture. The boss sends a message in the WhatsApp group at eleven at night, and you feel that not replying means you're "not hardworking enough". A colleague pushes work onto you, and you feel that pushing back means you're "not a team player". When a time boundary is violated, what you lose isn't just time — it's a sense of control over your own life.
Digital boundaries are the newest battlefield. A study by Anderl et al. (2024), which tracked screen-time data objectively, found that during periods of heavier phone use, participants reported lower psychological well-being and a weaker sense of social connectedness. And it runs both ways: more phone use, lower connectedness; lower connectedness, and you reach for the phone again. The researchers call it a "vicious cycle". Have you ever been with friends and yet couldn't stop scrolling? That urge to scroll is, to some degree, a sign of a blurred digital boundary.
The cost of having no boundaries
If you think "just grin and bear it and it'll pass", the research has news for you: it won't.
Rapp, Hughey and Kreiner (2021) studied 93 healthcare workers during the COVID-19 pandemic and found that boundary violations — which they termed "boundary-violating events" — were directly linked to the three dimensions of burnout: exhaustion, emotional detachment and a reduced sense of efficacy. Boundary violations took three forms: physical (work invading the space of home), temporal (working hours stretching on indefinitely) and cognitive (work information spilling over into private life). Each kind of violation was draining their psychological resources.
What's even more worth noting is that these boundary violations aren't some extreme event — they're the accumulation of everyday small things. The things you tell yourself are "no big deal": bringing work home, replying to messages late at night, checking email on holiday — they nibble away at your energy bit by bit.
Speed, Goldstein and Goldfried (2018) published an important review in Clinical Psychology: Science and Practice with a refreshingly blunt title: "Assertiveness Training: A Forgotten Evidence-Based Treatment". Sifting through decades of research, they found that a lack of assertiveness skills (including being unable to set boundaries) is linked to a whole range of psychological problems — social anxiety, depression, low self-esteem, relationship dissatisfaction.
This isn't a "just put up with it" situation. Every "no" you swallow tells your brain one thing: my needs don't matter. Repeat it enough times, and you'll genuinely come to believe it.
Why setting boundaries won't destroy your relationships
Many people don't dare to set boundaries, and their greatest fear is: "If I say no, the other person will leave."
This fear isn't unfounded — especially if, growing up, you learned that "expressing a need = being punished". But the research points to a counter-intuitive conclusion: relationships with boundaries are actually more stable.
The logic is quite simple. When you suppress your own needs over the long term, your body doesn't fail to notice — you accumulate resentment. And resentment is a slow poison for any relationship. On the surface you're going along with things; inside, you're keeping score. Then one day, over something tiny, all that suppression erupts at once. The other person has no idea what just happened, because in their eyes you'd always been "fine".
A boundary actually protects the relationship. It lets both sides know where the other's limits lie, so that you don't have to communicate through guesswork or through an explosion. It turns the unspoken rules into spoken ones.
Neff (2023), in a review article in Annual Review of Psychology, proposed the concept of "fierce self-compassion". She divides self-compassion into two faces: the tender side is gently keeping yourself company through pain; the fierce side is protecting your own needs — including setting boundaries, refusing unfair treatment, and speaking up for what you believe in.
Neff's research specifically notes that women are more prone to feeling guilty for saying "no", because society expects them to be forever gentle and forever accommodating. But her research makes one thing clear: saying "no" is itself an act of self-compassion. Your worth does not depend on how compliant you are towards others.
How to actually set boundaries: lessons from DBT and the evidence
Knowing that boundaries matter is one thing; doing it is another. The good news is that psychology doesn't just tell you "why" — it also tells you "how".
DEAR MAN: when you need to express a need
Marsha Linehan, the founder of Dialectical Behaviour Therapy (DBT), developed a set of interpersonal-effectiveness skills, and the most practical of them is DEAR MAN. This isn't some vague "just be brave" advice — it's a step-by-step framework for communicating:
Describe — start by describing the situation in factual terms, without judgement. "You've been more than half an hour late to our last three meet-ups", rather than "you're always late".
Express — state how you feel from an "I" perspective. "I feel disrespected", rather than "you don't respect me".
Assert — say clearly what you need. "I'd like you to be on time, or to let me know in advance if you'll be late." Don't assume the other person knows what you want.
Reinforce — explain the benefits of cooperating. "That way, we'll both enjoy our meet-ups more."
Mindful — don't get pulled off topic. If the other person starts dredging up old grievances, gently but firmly return to the matter at hand.
Appear confident — steady tone of voice, eye contact, open posture. Your body language should match your words.
Negotiate — be willing to find a solution both sides can accept, but don't give up your core need.
A study at Western Michigan University tested the effectiveness of DEAR MAN and found that people who used the technique were noticeably better at persuading others than a control group. But DEAR MAN isn't "manipulation" — its essence is that, while respecting the other person, you also respect yourself.
FAST: holding the line on your self-respect
DEAR MAN teaches you how to express a need; FAST teaches you how to set a boundary without losing your self-respect in the process:
Fair — be fair to yourself and to the other person. Don't over-concede out of guilt, and don't over-attack out of anger.
Apologies — apologise only when you've genuinely done something wrong. "Sorry, I can't work overtime tonight" — the "sorry" in that sentence is unnecessary. You have the right to choose how to use your own time.
Stick to values — don't do things that betray your own values just to please others. Compromise to keep the peace today, and tomorrow you'll be compromising over something bigger.
Truthful — don't exaggerate, don't play the victim, don't dress up a perfectly simple "no" with "because I'm really so busy".
DESC: a more streamlined framework
If DEAR MAN feels like too many steps for you, the DESC framework proposed by the psychologists Sharon and Gordon Bower is more concise:
Describe — describe the specific behaviour. "You're looking at your phone while I'm talking."
Express — express how you feel. "I feel as though you're not interested in what I'm saying."
Specify — make a specific request. "When we're talking, could we put our phones down first?"
Consequences — explain the positive outcome. "That way, we can both communicate properly."
What these frameworks have in common is this: they turn "setting a boundary" from a vague concept into a skill you can practise. You don't have to be a born expert at saying no — you can learn.
The most common traps when setting boundaries
Knowing the method doesn't mean smooth sailing. Here are the most common difficulties people run into when setting boundaries:
Over-explaining. You don't need to provide a ten-page justification for your boundary. "I want to rest by myself tonight" is enough. The more you explain, the more it looks as though you're defending yourself — and you don't need to defend yourself.
Waiting until your emotions boil over before setting one. If you always endure until the very last moment and then erupt, what the other person receives isn't your boundary but your temper. Boundaries are best set while you're still calm, not when you've already been pushed past your limit.
Expecting to get it right first time. Setting boundaries is an ongoing process, not a one-off declaration. This is especially true with people you've known for a long time — family, partners, old friends — who are already used to the old way of relating. When you set a boundary, they won't necessarily accept it straight away. That doesn't mean there's something wrong with your boundary; it means they need time to adjust.
Confusing "soft boundaries" with "hard boundaries". Some boundaries are negotiable: "I usually don't work overtime, but if you really need me to, I can occasionally." Some are immovable: "You can't throw things when you're angry." Being clear about which can be handled flexibly and which are non-negotiable will make your boundaries more effective.
Overlooking the fact that you might be a boundary-crosser too. Setting boundaries isn't a one-way affair. Before asking others to respect your boundaries, it's also worth asking yourself: have I, without realising it, crossed someone else's? Your self-awareness shouldn't only look outward — it should look inward too.
Setting boundaries within Hong Kong's cultural context
In the language of Western psychology, setting boundaries sounds perfectly natural. But in Hong Kong — a culture that prizes human warmth, places great weight on face, and emphasises the collective and harmony — setting boundaries is a great deal harder.
The line between "being warm-hearted" and "having no boundaries" is often blurred in Hong Kong families and workplaces. Parents flicking through an adult child's phone feels like a matter of course, because "I'm your mum". A boss messaging on a day off expects an immediate reply, because "we're all one team". A friend keeps borrowing money and never repays it, and you don't dare to chase it up, because it would "hurt the friendship".
But the "warmth" and "face" in these examples are really invoking the name of the relationship to demand that you give up your own needs. Genuine warm-heartedness shouldn't be built on one-sided sacrifice.
Setting boundaries within Chinese culture doesn't mean becoming "Westernised" or "selfish". It means: I value this relationship, so I choose to nurture it with honesty, rather than with suppression and resentment.
In practice, setting boundaries within Chinese culture may call for a few adjustments:
Use "I" rather than "you". "I've been under a lot of pressure lately and need a break" lands more easily than "you're putting too much on me". This isn't avoiding conflict — it's expressing your need while leaving the other person their dignity.
Connect first, then set the limit. "I know you're saying this out of care, but I'd like to handle this one myself" — first acknowledge the other person's motive, then express your boundary.
Go step by step. If you've never set a boundary before, don't expect to nail it all at once. Start with small things: turning down an invitation that doesn't matter much, saying "no" in a low-stakes situation. Every small act of practice retrains your brain to learn that after you say "no", the sky doesn't fall.
In closing
A boundary isn't something you set once and then you're done. It's more like an ongoing conversation — with others, and with yourself.
There will be times you do it well, and times you shrink back. You'll meet people who walk away after hearing your "no", and you'll also find that some relationships grow deeper because of your honesty. Both outcomes are very real, and they can happen at the same time.
At the end of their paper, Speed et al. (2018) offered an observation worth reflecting on: assertiveness training was once one of the most central skills in psychotherapy, but over the past few decades it has all but vanished from clinical training. We've gained ever fancier treatment models, yet forgotten one of the most basic capacities of all — knowing what you want, and then daring to speak up.
Perhaps after reading this article, you won't suddenly become someone who's "great at setting boundaries". But next time, when the words "sure, no problem" are about to leap off your tongue, maybe you'll pause for a second longer and ask yourself one question:
Is this "yes" something I genuinely want to say?
That one second of pause is where the boundary begins.
Want to get good at setting boundaries? Start with a hands-on course
Reading an article can help you understand the psychology behind boundaries, but real change takes practice. Just like the DEAR MAN and FAST techniques — understanding them isn't hard; using them is the challenge.
TreeholeHK's interpersonal communication course is built around the practical work of setting boundaries: how to speak up and say "no" in different situations, how to handle the other person's reaction, how to balance your own needs with maintaining the relationship in both the workplace and the family.
It's not a theory class — it's hands-on practice.
Further reading
If you find it especially hard to refuse others, there may be a deeper psychological mechanism at work behind it — not a personality flaw, but a learned fear response. Further reading: You're not soft-hearted, you're afraid to refuse — the psychology of the fear of saying "no"
Boundary problems are especially complicated at work, because they involve power relations and team culture. If you feel your boundaries being eroded at the office, take a look at: If you can't hold the line at work, it isn't because you're not firm enough
Before learning to set boundaries, it may help to understand your current boundary style first. Are your boundaries too loose, or too rigid? Is your boundary a wall, or a door with no lock?
References
Anderl, C., Hofer, M. K., & Chen, F. S. (2024). Directly-measured smartphone screen time predicts well-being and feelings of social connectedness. Journal of Social and Personal Relationships, 41(4), 1045–1065. https://doi.org/10.1177/02654075231158300
Cloud, H., & Townsend, J. (1992). Boundaries: When to say yes, how to say no to take control of your life. Zondervan.
Linehan, M. M. (2015). DBT skills training handouts an training handouts and worksheets (2nd ed.). Guilford Press.
Neff, K. D. (2023). Self-compassion: Theory, method, research, and intervention. Annual Review of Psychology, 74, 193–217. https://doi.org/10.1146/annurev-psych-032420-031047
Rapp, D. J., Hughey, J. M., & Kreiner, G. E. (2021). Boundary work as a buffer against burnout: Evidence from healthcare workers during the COVID-19 pandemic. Journal of Applied Psychology, 106(8), 1169–1187. https://doi.org/10.1037/apl0000937
Speed, B. C., Goldstein, B. L., & Goldfried, M. R. (2018). Assertiveness training: A forgotten evidence-based treatment. Clinical Psychology: Science and Practice, 25(1), e12216. https://doi.org/10.1111/cpsp.12216
Walker, P. (2013). Complex PTSD: From surviving to thriving. Azure Coyote.
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