Being a bit of an altaholic myself, there are some strange, strange things that I've seen happening in dungeons...
Of course, there's always the normal, confused people like the paladin in Scholomance yesterday who was pulling about 80dps. Using a one hander with no shield, he was specced into ret, wearing a helm with +47 spellpower with a BRD libram enchant for 10 stamina on it (?) and all of the rest of his gear was either mp5, "Of the boar", or "Of Spirit". I asked him if he had, you know, real gear and a weapon, because things were dying awfully slow, and of course I got the peevish "I'm not here for your critique man, I'm just here to play the game" garbage, self righteous mumbling that everyone else tries to pull. He ended up pulling all the students in the room in the middle, dying, saying I'm a bad tank and leaving the instance.
But seriously, the death knights... We were doing LBRS and this death knight somehow falls down into lower city from the very top of LBRS. Doesn't die, falls into a spot where he isn't moving in a safe spot, somehow... but then pulls a pack of mobs. Of course, our healer has a hot rolling on him from the top, and instantly, you see a bunch of names underneath us flash "CHANGING TARGET". Uhoh.. Death knight dies. Waiting, waiting... "Why didn't I get healed?" LOL. As we're laughing, we see the biggest swarm of mobs you've ever seen (Literally, the entire instance worth of mobs) charging at us, we make a futile attempt to stem the tide, kind of like seeing a Tsunami coming and putting up your umbrella, wipe and swear at the DK for a while.
We're doing Stratholme. I'm starting to tank mobs, as usual, the dps is doing nothing, but I notice something strange. I keep losing aggro randomly, to this Warrior who's doing about 1/3 of my damage.. I look at him, he's in Full General Gear from level 60, but he's using a sword & board. Wait a second.. is he full prot? Is he in d stance? He's actually taunting mobs? I ask him about it, he says "Oops, forgot to switch to fury" LOL. Yeah, I always forget to switch to fury when I'm *shockwaving* and *TAUNTING* mobs from my tank. I ask him if he can unforget and actually put on a weapon, silence ensues. He does the rest of the instance in Dstance, randomly taunting mobs at his own pace.
So many stories, not enough time. What do your PuGs do that is not just incompetent, but actually insane or completely unable to believe?