I'm nothing like my drug description =)

Heroin
You're capable of the highest highs and the lowest lows.
Addicted to feeling good, you'll do almost anything to avoid pain.
People seek you out, even though you can be quite moody. They're hooked on you!

I'm an optimist, I think any kind of challenge without pain isn't really a challenge at all. Oh well, at least the last part is accurate. The test was cool anyways, funny pictures