The act of camping and teabagging corpses while yelling profanities as a form of favourite pass-time is a fascinating yet objectionable social behaviour. I've seen a couple creative griefing in my time but generally others find it irritating and juvenile. I have done it several times in WoW. The PvP servers  makes it a very alluring environment and even encourages it. Hence when it comes to my opinion of griefing, my judging hammer will remain strictly in my pockets. However, of the times I take on the griefer personae, I try to do it in a creative and curse-free manner. I'm not against swearing but I find the challenge of not using it adds another dimension to the activity. It's even more rewarding when the victim acknowledges the ingenuity.

That said, I think it's a different story when griefing becomes an uncontrollable habit--that the only way to extract fun in a game is to jerk their e-peen and vomit expletives against their online peers time and time again. Hurrah, you've managed to make a dozen fewer friends. Way to go. 
 
The key to what I'd consider an acceptable form of griefing would be: 
 
1. to play within the rules of the game. i.e. no cheating! 
2. to offer an unique perspective of the gameplay to your victims. i.e. challenge them to be better at the game. 
3. don't take enjoyment out of being a jerk. If you like griefing because someone else's misfortune makes you happy; see a shrink. 
4. If you really must swear, make sure not to step over the bounds into obscenity. i.e. yelling racial slurs just makes you look like an ignorant fool. 
5. Be a good sport, offer a truce. They don't have to take it--after all, you probably made their life hell for a short while. But at the least, once you've tossed your e-peen around, the least you can do is wash it.