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.)
Last year, I had to choose what I would research in my honours year of my Computer Science degree. I actually remember thinking to myself, 'I'm going to use all of the techniques I have learned from LW'. I sat down for several hours, carefully analysing my situation, and came to the conclusion, I should research A. It is the superior option on every non-trivial metric I can think of. This is the rational decision.
But then, I chose to research B, because I would have been embarrassed to have to explain my choice of A to my family. And that was it.