I was watching the fourth OP opening and I thought of this: Which Straw Hat has had the saddest past? They've all been rightfully trauma'd, but who the most? Here's my rank, least to most:
7. Luffy: Shanks lost his arm, then left… not to much horror there.
6. Zoro: Yeah, Kuina died, but he still fights on in her honor, or something. Nothing too bad, in comparison to the others, anyway.
5. Usopp: His mother died, his father left. Sad, but not horrible.
4. Sanji: Starved on a rock, his soon-to-be mentor ate his own leg. Learned to never waste food. Hooray morals!
3. Chopper: His best (only) friend was poisoned... by Chopper himself. Then, he blew himself up. No friends. Pretty dang sad.
2. Nami: Now we get into the horrorble. Her entire town is taken over by pirates, and she watches her mother get shot in the head. Thrice.
1. Robin: Only survivor as she watched her entire island be unjustly genocide...ed. Yeah. No friends or family either, before that.
So, that's my analysis.