Good comments from Joe Offer. I agree that the best treatment for the really nasty is to ignore them. I avoid really nasty people. Moderately nasty people I am pleasant to...up to a point...sometimes they soften their attitude.

Quincy, a friend of mine also has a useful expression..."I make it a point never to get in a pissing match with a skunk."

And if I may quote Bob Dylan...(as I usually do)...

"Everything passes, everything changes, just do what you think you should do. And someday, maybe, who knows, baby, I'll come and be crying to you."