Bad sex

Let me start this article with a quote from the talented Billy Joel.

"There's nothing better than good sex. But bad sex? A peanut butter and jelly sandwich is better than bad sex."

Well I hate peanut butter, but totally agree on the gist of what Mr. Joel is saying.

Bad sex is terrible. It's awkward and uncomfortable and NEVERENDING!

Bad sex ruins me of my politeness and manners.

I once jumped up after it was over and spelled out a lame excuse just to dash out of his apartment.
I know it seems immature, but how long do you really want to lame in bed going over what a bad experience you just had?

So what's the key to good sex?