My group that my dad ran in highschool was a nightmare. We put the "ADD" into AD&D.
I paid attention, most of the time (yes Dad, even though I'm usually drawing or have my laptop open I do USUALLY have at least a working idea of what's going on), my friend was a space cadet, the boys had the attention span of a tsetse fly, and the thief was actually halfway competent. Not the character (or player) you want doing things unsupervised. She was the only one that paid attention when Dad was rattling off treasure and EXP totals, so naturally she'd just star what she was stealing, hand it to Dad, he'd nod, and then she'd write up a new list sans the starred items to the party as soon as they were done talking about whatever new book just came out or new song they'd downloaded. I didn't say anything because my character was in on it and quite frankly didn't give much of a hoot as long as she got a big enough cut for booze and a look at the shiny new swords and medium armor. Every once in a while ONE of the boys would notice her saying "Hey, I'm gonna steal this, ok?" (as after a while she just gave up trying to be sneaky about it) and start to throw a fit but then another would bring up some off-topic BS and he'd forget about it.
That thief also thought that since she was a DM for the highschool's club, she could tell my dad what was what who, you know, had only been playing the game since before she was born.
I've had a group break into a fist fight. Over what I don't even remember, probably something stupid and completely unrelated to the game. I tended to just try and ignore those two people in general. We've also had someone in our group try to steal from us. Oh yeah, and I've been stabbed with a pencil. I don't miss that party.
Being a role player in a group of roll players is always a pain. Half my party didn't even name their characters. That bugged the crap out of me.
OH! And our party that turned "evil," and by "evil" I mean "slaughter randomly and kill each other for no reason whatsoever." Chaotic Evil =/= mindless murderous psychopath. Hell. Even most sociopaths at least have SOME sort of motive. Not just, you know, because it's Tuesday. It's also just considered gaming etiquette to NOT kill a player who's bringing a new character into the party before he even has a chance to come into the party because you think it'd be funny. No joke, as soon as the DM asked the player to introduce his character another player started rolling dice to kill him. Just because. I'd still show up, but I stopped playing about the second time the party wiped themselves out for S&Gs and just curled up in the comfy couch and doodled. I was the only player that still had my original character because as soon as the party would start to bicker I'd just tell the DM I was getting up and leaving them to their idiocy. Half the time he didn't even notice.
My dad's the one with all the good ones not fueled by raging teen angst.