I hesitate to respond to iamb above, but I want to confirm that one can know this. It is by intuition one decides, though reason may be able to help. One can ultimately feel when something that does not fit or suit us has been shoved into our minds. Getting an experience to compare with that is the tricky part, often. One must experience how others lives and how others Think. Like I know damn well that I do not like wearing wool. There’s a chance, if all the clothes in my Culture had been made of wool, including the ones like underwear and shirts that directly touch the skin, I might not have known that my core self is happier with cotton, but can tolerate a woolen sweater over a long sleeve shirt.
This is not cultural. This is me, period. Given that I grew up where I could choose and hence had experiences of wool and not wool, it was easy for me to know. If not I might simply have felt that somethign was wrong, perhaps with me, since other people seemed ok or less whiney about wool. The water we swim in and all.
With many facets of Culture, family, psychology, language - we have nothing to compare it too. If one really trusts oneself - not easy to do, even brave - one may take seriously the feeling that somethign is wrong, things do not need to be like this, that sounds logical but I have the gut feeling it need not be the case or something better suited to me is out there. But it is hard to know…
If however one engages deeply with and in other Cultures, learns other languages, goes into altered states, is drawn to outsiders or alternative communities, radical thinkers, criminals, anything outside or different, one can begin to actually notice what one is ‘wearing’ so to speak, and see it as not simply the way things are, but one cultural garb amongst others. (If one is lucky and one’s parents are from different Cultures - not just different sexes from which one can also learn a lot - and who are fairly open to you exploring, this can get you off on a good start).
Nothing perfect or infallible in this, but one can feel when one is aligned or not aligned. There is a core self.
But one can Think one’s way out of respecting it.