Knock knock. Who's there? Olive.

Olive who? Olive your jokes are so funny!

Knock knock. Who's there? Silence.

Knock knock. Who's there? Existential Crisis.

Existential Crisis who? I'm not really sure, because the concept of identity and self is fleeting and meaningless in an infinite universe.

Knock knock. Who's there? The joke.

The joke who? The joke who was supposed to be original and unexpected, but now feels like it's just pointing out its own existence.