It all comes down to high self-esteem and social skills, or maybe just outright not caring about your appearance having influence in social spaces (except that this is obviously wrong, there's always bias towards conventionally attractive people).
As for me, I didn't feel anything positive nor negative as a teenager. I used to be very skinny, and several classmates had crushes on me. Strangers also harassed me since I was young which was uncomfortable, but didn't cause me any sort of repulsion towards my body. I started feeling more self-conscious when I was already 18 and gained a lot of weight. I can't handle looking at myself (my stomach and thighs are particularly atrocious), I hate going outside because that means I'll have to use clothes that don't fit me. My face looks off and weird whenever someone else takes a picture of myself, to the point where I think that's someone else instead of me. It's hard to believe my partner whenever he tells me I'm beautiful.
In some way, I'm grateful I'm not getting harassed anymore since I've changed and now I'm considered "fat and ugly" by society standards. I don't think my face is ugly by itself, but god I wish I could lose some weight and feel more confident in my own clothes again.