The Persistent Duck

A duck walks into a bar.

Duck: "Got any bread?" Barman: "No, sorry, we don't have any bread." Duck: "Got any bread?" Barman: "Look, we don't have any bread." Duck: "Got any bread?" Barman: "No!" Duck: "Got any bread?" Barman: "We don't have any bread!" Duck: "Got any bread?" Barman: "If you ask me if I've got any bread once more, I'm gonna nail your bill to this bar!" Duck: "Got any nails?" Barman: "NO!" Duck: "Got any bread?"