Originally Posted by R_Ravenclaw
I think they were alike in basic ways (i.e. arrogance and humour), but they were different in so many little ways. I think James knew what he wanted from life. He was a spoiled kid, and he had a good life. So one day he met this girl and knew that she was the one (not to sound cheesy or anything ;) ). In that way, I think James knew his mind well. But Sirius obviously dated around a lot. He didn't even seem to be really looking for the right girl. I see Sirius as a bit more reckless. I don't think James would've lost his temper (or however the prank came about) and told Snape how to get into the tunnel, where he knew full well that there was a werewolf.