There are two types of mistakes: mistakes of ambition and mistakes of sloth.
The first is the result of a decision to act -- to do something. This type of mistake is made with incomplete information, as it's impossible to have all the facts beforehand. This is to be encouraged. Fortune favors the bold.
The second is the result of a decision of sloth -- to not do something -- wherein we refuse to change a bad situation out of fear despite having all the facts. This is how learning experiences become terminal punishments... and poor job choices become lifelong prison sentences.
-- Timothy Ferriss, The 4-Hour Workweek
Huh. Kind of along the lines of what I was just saying.