I've donated blood three times through my high school, and it's much different than having a little blood testing done, given that the needle is roughly the size of a pencil lead. Even then, though, the pain isn't that great, and it's worth it anyway.

I think the most unenjoyable thing I've ever done is, either:

a) When I was in middle school, a student was giving away puppies at school. I said I'd take one, without asking my parents. When they came to my house later that day to have me pick one out, I asked my dad on the spot (I figured I'd have time to convince him - I didn't think they'd come that fast). He said "No", and made me go out and tell thim that I couldn't have one. That was hard.

b) When I was 11 or 12, I stole something from the store, because that's what the cool kids were doing at the time. I told my brother, who in turn told my parents, and my mom woke me up at my friend's house one morning with the most disappointed look on her face. My dad made me take it back and tell the storeowner what I had done. It was incredibly hard, but I'm glad I did it. Even with how disappointed my dad was, he was proud of me for manning up and admitting what I had done was wrong. In addition, the storeowner chose not to take it to the police, and I've been on good relations with him since. Stealing is bad.