I think certain types of humor require a level of sophistication that some people simply don't possess. Like, if it ain't slapstick, it ain't funny (Dick Van Dyke tripping over a chair or a little ol' lady slipping on the ice). Like some people's view of music, if it has more than three chords, it's just noise. That's why pop music is so pop....ular, you can be officially brain dead and still enjoy it.
I know a few people that are too uptight to find humor in anything, but very few of them are musicians. I think recognizing and enjoying good humor requires soul, sensitivity (to the human condition), tolerance (open to other's perception of the world), intellect (the ability to 'get it'), and finally, optimism (you can't see humor through a cloud of gloom and doom).
Obviously this does not apply to everyone. For some, it could just be a matter of taste. Also, just because I said it doesn't make it so

. Still, you gotta remember the old saying - Laugh, and the whole world laughs with you, cry, and you cry alone.
chas