Weirdest in a good way was in Fallout 3. I'm in the town built on an old ship in the harbor (forget the name). I try to pickpocket the waitress, but something went wrong, I think I actually tried to pickpocket the little boy with an attitude instead and got caught. Now, in Fallout 3, you can't kill kids, so I holster my gun and back away. He attacks me, which, because I don't fight back, draws the aggro of everyone around.
So we have this unkillable kid fighting with everyone in the market. Soon all the security forces join in as well. He gets hold of a gun and kills them all. Every single one of them. I then pulled him outside, where he ended up slaughtering the Brotherhood of Steel guys and a few Super Mutants. Pretty awesome.
Bad glitch would be Borderlands 2, in the Angel Core Control level, where Roland gets stuck 3/4ths through the fight and all mobs stop spawning. I'm just wandering around, waiting for more robots to appear, or something, when I notice Roland stuck up in the air. I eventually had to save and quit then continue, so I could do the whole thing over. The sad part is that the boss immediately before this section, BNK-3R or something, got stuck while doing his dying animation, so even though I killed him, I had to do the entire fight over and kill him again. Ugh.
