Pokemon. Not the trainers, the 'mons themselves. Yeah, you get awesome superpowers, but you get smacked in the head with a baseball and suddenly you have to obey a ten-year-old or live in a computer box for the rest of your life. That certainly sucks.
Anyone in Resident Evil (except Wesker). Zombies. Freaking Zombies... plus no weapons and ammunition. And what is your reward? anonymity/cover-up and a lousy government paycheck. F that.
Mario. Going to the bathroom must be a nightmare in a world where squatting on pipes sucks you through them.
Superman. On the one hand... you're freaking SUPERMAN. On the other hand, you have to live inside horrible game worlds. You think it's bad to play Superman games, imagine how horrible it must be to live in one. Speaking of...
The Desert Bus driver. The worlds most boring game. A game so terrible, LoadingReadyRun and friends hold a "Survivor" reality show/telethon to see how long they can stand to play it (for charity, of course!) Imagine not being able to leave... forced to drive that bus through the desert, no landmarks, no destination, nobody else to talk to, no towns to stop in... forever. *shudder*