Good or bad joke?

If they laugh, sputter, or exhale quickly, they think it's a good joke.
If they tell it to all their friends, they think it's a great joke.
If they groan, they think it's a bad joke.
If they groan AND tell it to all their friends, they may be messing with you (Ha, you can't make me laugh, I won't let you neener neener.)
If they don't laugh, they think it's a bad joke.
If they don't laugh, but have the "deer in the headlights" look, they didn't get it. It might still be a good joke, particularly if the audience do not speak English as a native language.