Poor judgement

Going out in a violent winter storm, alone, at night, in t-shirt and shorts, with no PFD, after drinking a six pack. Oh, and you don't know how to swim and have night blindness!

The thing to remember is just because you don't die doing something stupid does mean what you did is safe. The nature of risk is that it is a probability. Chances are that if you do something risky, you will survive. Poor judgement just increases the chances that something will go wrong, and it can increase the severity of the consequences. Unfortunately, good judgement often is learned through experience and experience is what you get when you had poor judgement.