Task: Tell me why this joke’s not funny.
input: Knock knock!
Who’s there?
Banana.
Banana who?
Knock knock!
Who’s there?
Banana. 
Banana who?
Knock knock!
Who’s there?
Orange. 
Orange who?
Orange you glad I didn’t say banana?
output: It’s a knock knock joke that’s based on a really weak pun, and it’s been so overused.