2. I would have stopped comparing myself to others since the first year of high school: I was almost always top of my class but the constant comparisons and fear to be a "loser" even for a single score have greatly contributed to my extremely deep depression; I can't find joy in my accomplishment: it doesn't matter how good I am.
3. I would have tried to be more physically attractive both for a health and social reason: I would have dropped all the b*it about interior beauty and focusing on having a good looking package to pass the initial first-impression, instinctive reaction.
4. I wouldn't have thought much about the future and how much I need to do everything right or else. It turns out that I do not have and will never have all the information to do the right choice in every given context and most of the good and the bad in life are happenstances, luck: our right choices are a nice narrative that we tell ourselves to make sense of the mess that it is existence.
5. I would have stayed a bookworm even if it was not cool: the cool kids turned out to be not so cool after all.
6. I would have started watching more anime in high school instead of being snobbish about it.
7. I would have tried to develop much more my interpersonal skills with people I was really interested about instead of the above-mentioned cool kids.
8. I would have dropped all the lofty multi-year goals and expectation and focused on small goals (at most 6-12 months-long goals) and create sustainable habits on the day to day mundane grind so that, when the realization that the goals were impossible would have hit, I would have been sustained by a healthy lifestyle instead of my big mess of a so-called life.