It's kind of a funny thing. You do the best you can all the time, you usually double-check yourself. But now and then you notice that you forgot something, or, you made a mistake. So, you say next time you'll be more careful, and next time you are.
Most of the time the "mistake" means nothing, but sometimes, the wrong mistake happens at the wrong time.
When you've flown long enough, sooner or later you meet a pilot, or two, who's a real fool. But, as fate would have it, he retires happy.
EK Gann? "Fate is the hunter."
It is very sad.