I was just playing in a 3v3 Cataract.  The opposing player had the worst attitude of anybody I have ever played any video game with, ever.  He spent the entire time completely insulting everyone, along with his 2nd teammate.  He kept calling his third teammate a complete retard, saying things like "I think that Ickytotem must have been born in the rivers of a third world country he is so stupid" and "This person lacks an education" and "Dude, do yourself a favor and just return your copy of this game because your horrible" "When your teammate is a complete retard, its gg."

This is NOT good.  People should not be doing this because you don't know the life of the person on the other end of the computer, and you don't know what they have been through.  Just leave if you have such a problem, but relax with the negativity.  There should be an official reputation system so people can rate others.