I'll go first.

The best decision I ever made was to start traveling. I grew up in a small, rural, deeply religious town. There was definitely only one acceptable way of seeing things. Getting outside of this town and outside of this country helped me really see how isolated and uninformed many people in my hometown were. Getting to know life in other places, the people in other places, the things they believe, their perspective on life and the world, and the struggles they go through, really opened my eyes in more ways than I can even begin to enumerate.

Probably the worst decision I ever made was buying a project car (aka, the Money Pit). I fell in love with this car and wanted to restore it and make it better than ever. I ended up spending about twice as much as the car itself cost. One day it got hit while parked on the street by a hit and run driver, smashing in the whole left side. icon_evil.gif