I only use cheats once I've beaten a game. I also follow the lesson I was taught early in life about if you don't have anything nice to say, then don't say anything at all, and this transferred to my online play where I usually have my mic off unless someone talks to me.
When playing with friends however. That right there is a different story, as I will never do anything cheap online against strangers, but when it's friends only expect to see noobtube spam, helicopter and tank whoring, and mass camping. We will trash talk like crazy to eachother, and teabag EVERYTHING, and this includes our own corpses (that one is mostly me, but whatever). When I play with friends I enter fun mode, I stop trying to win, and start trying to screw everything up. I once killed my entire team in a friends only game, and started to say that I won us the game, in response to this all of my friends on the opposite team suicided so we actaully did win... my friends are awesome (this was Halo 3).