Nicholas Hopkins Excessive caution in one-shots is a pet peeve of mine.

Jason Morningstar makes a good point about brutalization. I ran a god-awful game of Mouse Guard for some guys that were very obviously a) not used to this kind of game and b) seemed regularly abused by their GMs. One especially damaged guy was asking me endless questions about mouse physics before we began, and no amount of me saying “Look, don’t worry about it, I’m not here to screw you over; It’s not that kind of game” could do anything to abate it.