I realize I may get flamed for this thread, but here goes:
I've been playing a lot of Death Knight recently, and I've noticed that whenever my opponent draws a Blood Plague or I use The Primus's Runes of Blood ability, I make nomnomnom noises to myself as I eat up that delicious health. I started doing it sort of unconsciously at first, but now I lean into it, smacking my lips with relish. It's stupid and silly, but it increases the fun I'm having while I play.
So, what do all you freaks out there do while you play that makes the game more fun for you? Scream out your favorite minions' call lines when you summon them? Chant FACE or SMORC when smacking the opponent? I'm sure some of you have some silly little things you'd like to share.