Then they call you a cab?

That joke goes back at least as far as William S Gilbert. He was tall and
authoritative-looking. A man mistook him for one of those people who stand of
hotels, and asked him to "Call me a cab".

"Very well... You're a four-wheeler."

"Wha...?"

"You said to call you a cab -- and I couldn't very well call you hansom."
(punning on handsome)