Things I'd do well at:
Being a space marine, being a mysoginistic wanker who kicks alien ass (good old Duke nukem), kicking ass of human and non-human origin, commanding armies, fighting with weapons or bare hands in one-to-one fights, hacking and slashing my way through hordes of enemies and using magic/demon powers, being the good guy, liberating red planets, playing the guitar, being a medic and cooking.
Things I'd do badly at:
Being evil, driving, playing sports, dodging bullets, sniping, being a wizard/adept/engineer, coming up with things to do while wandering the post-apocolyptic wastes, keeping to deadlines, making my mind up, waiting for my go, using disguises and golf.