Knock knock. Who's there? Anita.

Anita who? Anita little help with these heavy bags!

Knock knock. Who's there? Nobody.

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

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? Wire.

Wire who? Wire you not opening the door?