I have, on a number of occasions, made serious mistakes. On several occasions people have asked me "why didn't you X". Sometimes the answer is "I was stupid and

I have, on a number of occasions, made serious mistakes. On several occasions people have asked me "why didn't you X". Sometimes the answer is "I was stupid and irresponsible". This makes me feel bad, and rightly so. Other times the answer is "I didn't know I could X." Those are the times when I'm very glad someone asked me the "mean and thoughtless" question. Concrete example: a friend of mine graduated coding bootcamp and has been interviewing for her first job. After complaining to me about 2-3 interviews in a row where she bombed questions on the same topic (I think inner joins), I asked a mean and thoughtless question: "why don't you maintain a queue of topics you screw up on interviews, and study one topic each day". Her answer was "I've got no good reason for not doing that". So she made a queue. Then she shrank the queue. The number of questions she messed up started going down. Now she has a job.