Luck said himself that he was mentally broken, the cycle of injury, pain, rehab, injury, pain, rehab was too much and the only way to break that cycle was to step away from football. He also said that he promised himself he wouldn't play through pain again. I'm not saying he's wrong for retiring, I actually think it's the smart thing to do. But you can't call an act selfless when the act was done to take care of yourself.