I remember having warlock 497 in random dungeon que. He claimed that he is doing all job and when he was in quest greens he did 50k single target dps. He died (because healer "lagged" when warlock was standing on shadow-orb-thingie-before-last-boss) and we kicked him out of dungeon while he was swearing at healer for being scrub.
Oh, and yesterday i did 5-8k DPS in my tank gear as boomkin on 89 lvl alt. I am so bad at this game.
I just want to point out, that doing more dps is not equal to carrying the dungeon. Healing ass out of 4 melee without tank (having ret qued as tank to get instant proc) is carrying, not doing more damage. There is no enrage timers, and no one dies in dungeons becaouse of lack of dps.