Knock, knock.
Who's there?
Banana.
Banana who?
Orange.
Orange who?
Orange you glad I didn't say banana again?
Alright listen up, genius. This is a knock-knock joke. The setup repeats 'banana' to set a pattern. Then, it breaks the pattern with 'orange', leading to the pun 'Orange you glad...' It's funny 'cause it's unexpected and kinda dumb. And you, my friend, are exactly the kinda person who'd fall for this, aren't ya?