Yeah, the LFD thing is a curse in disguise.
Logged on my Druid, joined a Zul'Aman run where the DPS was struggling to pass me in DPS and Damage Done (I was tanking) and the healer had issues keeping me alive since the moment he went from Holy Light spam to Divine Light, he'd run out of mana. Turns out he was wearing a mix of BOE epics and ilvl 272 greens. We wiped on the second trash gauntlet (the one with the scouts that call in reinforcements) because the healer decided to pull one of the scouts with his weak *** Judgement and when the reinforcements came, they ran right past the group of trash mobs, including two scouts, I was about to pull.
I told him he was a ****** for pulling scouts like that. He told me I was the one who pulled the group. Apparently he turned blind the second he hit that Judgement button, because the reinforcements ran right past the group, pulled them and then went for the healer. Left without bothering with the discussion. DPS was way too low for the healer's mana pool anyway (he ran out of mana every pull about halfway through the fight).
Logged on my Shaman instead and joined another Zul'Aman run, this time as the healer. The tank was a T12 geared Warrior with both the Brewfest stamina trinkets. The Warlock was so busy telling the Warrior what a scrub he was (didn't have issues healing him) that his own DPS never went above 10k. After we wiped when some DPS pulled a patrol and the tank ran to help without letting me know and the Warlock simultaneously pulled a group of mobs because we were taking too long, in his opinion, I just left.
I was ready to snap someone's neck at that point.