Agree with all that has been said.
You can't forget the terrible pax. You can remember them and talk about them for months after.
But the polite ones you definately remember them - at least for the rest of the flight or that evening when you get to the hotel/home. It makes it worth it; the person who wwalked to the galley to ask for a drink rather than pushing the call button, the person who upon disembarking thanks you for excellent service.
Also not forgetting the stunning guy who says you are gorgeous (modest aren't I!) in a very sincere and non-creepy way - very flattering when you know full well he could probably have any gal he wants!