How hard does he actually work,
HE is a one trick-pony. All he knows how to do is fight.
Everyone else, does the 'thinking' for him, so that by the time he has to make tough decisions, the situation/stakes have been so ferociously spoon-fed to him, his decisions are always such obvious choises.
NAMI: This is a really really bad guy
LUFFY: Oh then I'm gonna beat him up.