Why do the speakers decide to go to the gas station?

M: What’s happened to my order? I’ve been kept waiting for over haft an hour already.
W: I’m very sorry, sir. I will ask right away.
M: Well, please hurry up. I can’t wait much longer.
W: One moment please. (A moment later) I’m sorry to have kept you waiting, sir. Your order will be here in a minute.
M: I have a train to catch.
W: Yes, sir. Oh, here is your order. Once again, our deepest a pologies.