There seem to be a lot of stereotypes of players on either faction: Allies are kiddies and goody-goodies; Hordies are bloodthirsty, basement-dwelling jerks who don't even play nicely with each other. If I come across someone who seems like a total stooge, the thought, "That guy probably rolls Alliance." crosses my mind. I've discovered that these are merely overgeneralizations and there are great players and great people on both sides. Maybe I won't pick fights with chicks who play gnome when Wrath of the Lich King is released.
What's your experience with faction rivalry beyond Azeroth?