Ignorance is not stupidity, but it might as well be. - Lois McMaster Bujold

A few other works, half of which turn out to be rubbish. Always a problem with written sources, which frequently tell you far more about the person who wrote them than the subject addressed.

Successes are secret and thankless, failures are splashy and gain you only blame.

It only takes one nutcase to decide that you, not he, are the reason his life sucks, and set out to even the score. Nutcases are not in short supply here.