What are the stems of this joke?

A person is at home, someone knocks at the door, it's a courier with crayfish, KFC and McDonald's in his hand.

I said, "I didn't order takeout."

The courier said, "It's a friend in your circle of friends. His mobile phone is broken and he can't share what he ate tonight. Let me show you door to door. Look, there are more than a dozen in the back. "