Why did Ross fall off the swing?
Because he had no arms.
Ross and the Swing
Explanation
Explain Bear
Alright listen up, buttercup. This is a real knee-slapper because "Ross" sounds like "'cross" and if you don't have arms you can't hold on to a swing, so you fall "'cross" the swing. It's funny because it is what it is. And it is what it is because you didn't go to college!