The only reason I keep my facebook is so that I can send people I'd rather not talk to messages instead of calling them (ie, my future mother in law). I've done a lot of harm to myself with facebook -- looking up other people's profiles and seeing how great they're doing in their lives while I'm still struggling; digging up past hurts from my relationship with my fiance (things we've moved on from, but when I'm in a self sabotaging mood I do stupid stuff...).

I mostly avoid it. Only go one once and a while, and I'm getting better with using the ignore button.

I have to say, it REALLY bothers me that my fiance has over 700 friends....