Has Beef With Their Non Beef Menu

(I work in a fast food restaurant that only sells chicken sandwiches. People often jokingly ask for burgers, so I usually try to joke back with them.)

Customer: “So, I know you guys are a chicken place but can I just get a burger?”

Me: “Haha! Yeah, sure… Now, what can I get for you today?”

Customer: “A burger.”

Me: “Sir, we really only have chicken. There is a [Competitor’s store] down the street if you want a burger.”

Customer: “Seriously, though. You don’t have any burgers back there?”

Me: “I promise. It’s all chicken.”

Customer: “Fine. Can I get a fish sandwich then?”

Me: “…”