I'm pretty good at recognizing humor and understanding humor, but it doesn't translate to invoking a laugh out of me. I can watch Family Guy and catch every political, pop-culture sarcastic joke, but it probably won't make me laugh out loud. Same with the Simpsons and South Park.
It's just mostly how you grew up and what you got accustomed to. I didn't grow up on TV humor and shit. I'd laugh when my friend would fall off a tree, but I wouldn't laugh if Johnny Knoxville fell of it on MTV.