The Deeply Stupid Are Immune to Sarcasm

Customer to employee: Excuse me, are these zucchini?
Employee: No, they're pickles.
Customer: Are you sure? They look like zucchini!
Employee: Yes, they're pickles.
Customer: Oh. (pause) Do they taste like zucchini?
Employee, after long pause: Yes. Yeah...pickles tastes like zucchini.

--Balducci's Restaurant