I love how words that are usually used to show you like someone can be turned around and used aggressively.

My favourite comes from Dead Like Me (I think that's where I saw it) where two guys are about to get into a fight and the first calls the second one friend and the second one says "I'm not your friend, FRIEND!" and you know they are going to punch each other in about a second and a half.

Other good ones include, but are not limited to:

Sport

Pal

Friend

Chum

Buddy