This guy I played with was a great player, but not a very good DM. He would have great story ideas, but there were a few problems..
He LOVED Dwarves. He thought Dwarves were the "master race" of DnD.
He had an NPC join the party. Oh, what race? hahaha...
The Dwarven Fighter that joined us was named... Gilmi. Yes, Gilmi.
So, we're in a well-thought out dungeon, involved in a well-thought out story. Sure, Gilmi was annoying as hell, but the adventure was actually pretty fun. And we're kickin' ass and we know we're nearing the end, when we come to a "Y" intersection, forced to choose between left and right.
Player 1: OK, guys. We usually rock-paper-scissors on these left or right scenarios, but I'm really feelin' the left this time.
Me: Yeah, let's just go left. R-P-S has kinda screwed us. Think we've went to the well one too many times.
Player 3: I adjust my armor a bit after the last fight, nod firmly, and begin leading down the left corridor.. sword held ready.
DM: Gilmi heads down the right corridor.
Player 1: What the...? Fine, that #*^&ing Dwarf is annoying anyway.
Player 3: Since I'm in the lead, I assume the rest are following. I don't bother to notice Gilmi heading off.
Me: Ha, going off alone.. there's gonna be some Dwarf-kabobs at the end of a goblin torture-staff!
Player 4: Short little piece of....
So, we get to the chamber with the BBEG. Standing there in all of his glory. His 5 minions stand on the points of a pentagram etched on the floor, with him in the middle. An epic battle ensues, with one of the group falling unconsious and another getting dangerously low. Thoughtful tactics, lucky rolls, and plain old balls-deep attitude wins the day! We go through their belongings, and head back. We reach the "Y" intersection...
DM: Gilmi comes heading down the hallway, carrying an armload of treasure....
Gilmi knew right where the treasure was. He was at full hp and we were wounded. He decided that since he got all of that treasure by himself, he would keep it. We could keep what we took off the guys.
Player 1: *nods to me* OK, Gilmi. That seems fair. Afterall, you did pick the right hall. (I pat Gilmi on the shoulder, nodding to him *moves character over beside Gilmi on the mat*)
Me: Yeah, I guess we should have listened. Maybe we can work out a trade with some stuff you got there? (I go over to see what all Gilmi has *moves character*)
Player 3: WHAT THE HELL?! THAT LITTLE DWARF LEAVES AND MAKES US FIGHT AND NOW HE GETS TO KEEP THE BEST LOOT. THIS IS BULL! *moves character down the hall a bit, away* (winks at me)
Player 4: *Shrugs*
DM: I'm glad we understand each other. Gilmi shows you some of the things he found, including a bastard sword and a suit of chain mail. He takes his pack off and opens it, showing you the fine items.
Player 1: This round, I stab the hell out of the now-unarmed Gilmi.
Me: Since it seems I'm on the opposite side of Gilmi, it appears we have him flanked...
Player 3: I'm going to be casting Magic Missle....
Player 4: Holy hell, you guys are pullin' some gangsta $#*^! Mandon laughs and draws his bow this round.
DM: ....no!
In the end, Gilmi ended up dead without putting up much of a fight under our assault. The DM looked... disturbed. I actually thought he was going to yell. Gilmi finally got his axe out, but both of his attack rolls were horrible flops, while the dice-gods seemed to be on our side. I guess it was fate.
Anyway, we make it back to town without any bandit attacks or roaming goblins or such. We thought things had calmed down, when we were apprehended at the gate for Gilmi's murder. That's right, arrested and hanged for murder.
.....Later that night, after the DM had went to sleep... Players 1, 3, and myself filled his shoes with ketchup and mayo, his hands with shaving cream, a little mustard in each ear, and some hot sauce in one nostril before he woke up yelling... rubbing at his face and nose with shaving-creamed hands.
He went to put on his shoes, talking about how he was "outta here"....
Eventually, he calmed down.. laughed about the whole thing.. and agreed to never DM again.