What makes it funny? Forget it.

Humor can be dissected as a frog can, but the thing dies in the process and the innards are discouraging to any but the pure scientific mind.
-E. B. White (1899-1985) Some Remarks on Humor 
The listener who doesn't understand a joke, won't find it funny, even after it's explained. Since I usually know my audience, I  tell  jokes my audience will appreciate.  But when I'm with an audience with which I'm completely at ease, I prefer whimsy and the absurd over joke telling. And there is no way that this type of humor can be made funny by explanation either.