Knock knock. Who's there? This is a knock-knock joke.

This is a knock-knock joke who? Just trying to figure out where we go from here.

Knock knock. Who's there? A pause.

A pause who? No, just a pause. The joke's over.

Knock knock. Who's there? Wu

Wu who? Wu don't know, I'm having an identity crisis!

Knock knock. Who's there? Existential Crisis.

Existential Crisis who? I'm not sure, but the meaninglessness of this joke is a reflection of the void that lies at the heart of our existence.