Whatever else an American believes or disbelieves about himself, he is absolutely sure he has a sense of humor.
Analyzing humor is like dissecting a frog. Few people are interested and the frog dies of it.
English usage is sometimes more than mere taste, judgment and education – sometimes it’s sheer luck, like getting across the street.
The only sense that is common in the long run, is the sense of change and we all instinctively avoid it.