Re: everyone else, thank you for your replies
I think it's necessary for me to give a bit more personal detail. I'll leave it to the forum to decide whether this is type-related or not. (All my type information is in my sig.)
I tend to view myself as having a few core strengths and core weaknesses. As I've gotten older and more mature -- I'm 22 now -- my strengths have amplified and my weaknesses have diminished, to a degree that I personally find pretty shocking, though I don't know how others perceive it. Thus, much more than other people I know, I tend to see my "self" on a timeline: I used to be an overbearing asshole, now I'm not. I used to be unable to keep myself from calling people out on their bullshit, and now I've gained that skill. I used to be selfish, a bad listener, and not the best friend a person could have. Now I am the opposite. Frankly, I look back on myself, and I'm ashamed -- and even though part of me is concerned that, a decade from now, I'll realize that I was a 22-year-old asshole too, I'm pretty happy with how I've turned out when I compare present-day me to past me.
As a result of all of this, my personality has been shaped to include this view, and this insecurity:
The view = that every core aspect of myself can vary widely given the situation, that it's all essentially temporary, and that it takes willpower to stay "good", as my tendency (from being Te-dom and a 1w2) is to be "bad" (i.e. blunt, domineering, quick to make enemies, not self-aware).
The insecurity = that everything I value about myself could be reversed in an instant, and that I couldn't gain it back. That something similar to the change that occurred in me from my early teens to my early twenties, could happen again, in a bad way -- with a vengeance.
I had a dream, a week or so ago, where I went to a hairstylist, told them just to give me a trim, and they chopped my hair down from its current (and recent) long length, to the short length where it was for almost the past ten years. I was absolutely mortified, and when I woke up, the first thing I did was put my hand up to my head to see if all my hair was still there. I mention this because the symbolism is pretty clear, and proves both the above view and the above insecurity.
So... again, I don't know how much of that is type-related (or at least, type-typical), but that's where I'm coming from with this thread. If I do something "wrong", there isn't a concrete sense of "that wasn't ME, that doesn't define me", because "me" has changed so much, that even with those core strengths/weaknesses that I'm certain about, I don't have a strong sense of a permanent "me". And from what I understand of self-acceptance, you need to be able to accept your weaknesses, as if they are unchanging.