This is a repository for major, life-altering mistakes that you or others have made. Detailed accounts of specific mistakes are welcome, and so are mentions of general classes of mistakes that people often make. If similar repositories already exist (inside or outside of LW), links are greatly appreciated.
The purpose of this repository is to collect information about serious misjudgements and mistakes in order to help people avoid similar mistakes. (I am posting this repository because I'm trying to conduct a premortem on my life and figure out what catastrophic risks may screw me over in the near or far future.)
Seconded.
A bit further: Placing little value or interest on personal style, not learning how basic style works, not owning any formal or even smart casual clothes at all, not knowing what terms mean and where they have broken up. This results in you going on really annoying (and maybe expensive) shopping trips under time constraint and makes you vulnerable to cultural guardians and merchants when you eventually are forced to figure out what the hell you are doing.