A duck goes into a bar, and asks the bartender, "Got lunch?"
The bartender replies, "We don't serve lunch in here."
The duck leaves.

Next day, the same duck goes into the same bar, and asks the bartender, "Got lunch?"
The bartender, looking stern, replies, "Look, I told you yesterday we don't serve lunch in here. I'm telling you today, we DO NOT serve lunch here. If you ask me again, I'm going to nail your webbed feet to the bar. Now leave!"

Next day, the same duck goes into the same bar, and asks the bartender, "Got nails?"
The bartender replies, "No, we don't have any nails."
The duck then asks, "Got lunch?"