Aside from my wife, whom I personally taught to play the game, my current group is a transplant for me. I sort of replaced their old DM who decided to stop running stuff for them. And now I kind of understand why. One of the players just never seemed to bother to learn the rules, from which I gather the old DM just always told her what to roll. Another player knows the rules after a fashion but is more interested in making weird characters than actually making those characters follow rules. Another player is just very ingrained in his ways and has difficulty adapting. Not that I think that this was necessarily all the previous DM's fault. It's just a quirky group, one that I have decided not to DM for myself, although I still join them as a player with one of the other players as our DM now. I like them all as people, but as players, they all seem to want something very different out of the game and are very difficult to please.