I always choose fast learner first.
I don't ever give my sims rewards like steel bladder or fireproof or anything like that. I find it amusing when they end up peeing themselves for whatever reason. I fear that my game might become too boring for me if my sims didn't have to take care of their needs. If they're in danger of any kind, I sometimes pull their need bars up, but only in an emergency really.
Also, I saw two sims become overheated the other day at SV festival, and they both burst into flame. That was hilarious, I've never seen that happen before.
