I'm sure it will come as no surprise to anyone who has ever PuG 'ed into LFR or LFD or even just watched /trade channel for a while that there are some very rude people who play this game.
In case you haven't done any of the above, allow me to give an example from today. I jumped into LFR to see if I could pick up some healing gear to give healing a try, and I won the gloves token. Well we get to the next boss's trash and another paladin whispers me something in another language. I reply "huh? " assuming that he's wrong channeled me, but I get on with pulling slimes and the next thing I know I'm being sworn at. I look back through my whispers and see he's asking if he can have the hand token. That in and of itself is fine, some people roll on things they don't REALLY need, but in the space of 2 minutes to switch to swearing and questioning sexuality ... doesn't really sell your case of getting the token handed over.
Oh well now that's off my chest :)