Hello Erecura: I wish I knew the answer to this. I don't. Neither do I know what causes it... something in one's upbringing or one's genetics I suppose. I do think part of this comes down to not feeling comfortable within yourself... feeling like you're not worthy. You feel as though there is an emptiness inside. And so you try to fill it by constantly seeking the approval of others... often at your own expense.

I'm an older person now & I live a pretty-much entirely solitary lifestyle. But when I was young, fitting in was very important to me as well. I would have to say though, in my case, it didn't last. As I grew into adulthood I became, if anything, argumentative.

Anyway, I don't know how one goes about learning to be more assertive. There used to be assertiveness training programs one could take. Perhaps there still are... I don't know. Unfortunately, knowing how to be assertive, & feeling comfortable with it, can be two different things. So it is perfectly possible to know all of the assertiveness skills but to be dying inside when one attempts to practice them.

The positive thing here is that you know you have this problem. So being aware of your tendency is a step in the right direction. Perhaps one important thing to do is to simply try to be aware of situations you are approaching where needing to be more assertive than you feel comfortable with / setting boundaries may be necessary. Perhaps fostering this type of awareness will make it possible for you to navigate around at least some of these types of situations. And then, beyond that, perhaps working with a therapist regarding these issues will help you to become more comfortable asserting yourself.

At the end of the day, as the saying goes, I think what is most important is that a person learn to accept her or himself just as s/he is & not try to become something one is not. There is a danger in imagining what one would like to be like, & then constantly measuring one's actual day-to-day performance against that ideal. One seldom, if ever, measures up. So there is a tendency to repeatedly beat oneself up for not being as good as one believes one should be. And simply becoming more comfortable with yourself, just as you are, may go a long way towards filling in that internal emptiness & helping you to stop seeking the approval of others at your own expense.