I try to sell them pizza or try to strike up a conversation on something strange. Philosophy or obscure history. Not mean, but it can be interesting.

The best was a friend of mine,
Them: "Hello I'm ******..."
Him: "They're under the bed."
Them: "Who is sir?"
Him: "Commies."
Them: "What?"
Him: "Nikita Khrushchev is under my **** bed."