A duck walks into a bar and up to the bartender. Looking the fellow square in the eye, he asks, "Hey, uh, you got any fish here?"
"No," the bartender replies. "This is a bar. We do not sell fish. If you want something to drink, I can help you. Otherwise, scram." The duck waddles away, muttering to himself.
The next day the duck returns, bellies up to the bar, and asks the bartender, "Say, um...you got any fish?"
"No, no, a thousand times no!" cries the bartender. "Look, I told you yesterday—we don't have any fish. If you ask me one more time, I'm going to nail your stupid little duck bill to the bar. Got it?"
"Yeah, yeah, I got it, I got it, mister," the duck mumbles, slides off his barstool and waddles into the night.
The very next day the duck is back. "Er, mister?" he begins.
"Yes?" replies the bartender with a menacing look in his eye.
"Do you...do you have any nails?" the duck asks.
The bartender frowns. "No. This is a bar. I have no nails."
"Well, uh...you got any fish?"