@Setanta,
I remember several, but I'm not done yet. I intend to have more folly. It's only through folly that I learn where I want to go next.
One big folly? Hummmm. I got married when I was sixteen because I thought I knew better than my mother and other adults. And for me, in that case, it was true. But that's just because I had a certain set of circumstances in my life that many others do not. The day I got married was a great day to me because no one, other than the police, could tell me what to do and what to try again. Still I count that decision to marry as a mistake. If I'd known then how short life is and how soon I'd be able to call my own shots, I would have waited and avoided the misery of that early marriage. Still I learned and continue to do so.