Or the variation on GC's quote above, favored by Craig Anderton: never wrestle with a pig; you'll only get muddy and the pig likes it.
In most social situations, you decide who
you want to interact with. If you get into an altercation with someone online, it's because
you chose to. I know, sometimes it's hard to resist. But ultimately the choices are always yours.
For example, I will never, ever, type the word "becan" in a forum post. It invites the wrong crowd.