Inside Joke

This afternoon my daughter and I took her mother for a Mother’s Day treat at the Cold Stone Creamery. A little sign there said “Friends don’t let friends eat grocery store ice cream. Indulge responsibly.” It struck me how so much of American humor does not stand on it’s own but makes reference to something else. Parody seems to be an almost default genre for my college video students year after year. I was wondering if this is part of the human condition or is it an American or western thing? I’d be interested in finding out.