Knock knock. Who's there? Purpose.

Purpose who? That's what I've been asking myself for years.

Knock knock. Who's there? Brew.

Brew who? Tea-rific to meet you.

Knock knock. Who's there? Nobody.

Nobody who? Exactly. Why are you talking to the door?

Knock knock. Who's there? Peas.

Peas who? Peas-fully waiting for you to open the door!