Strange Duck

A duck goes into a bar and askes the bartender, "You got any fish?" The bartender replies, "No, this is a bar and we don't sell fish," so the duck leaves. The next day, the duck goes back to the bar and asks, "You got any fish?" The bartender says, "I told you yesterday, this is a bar and we don't sell fish!" The following day the duck returns and says, "You got any fish?" The bartender loses it, grabs the duck by the neck and screams, "I TOLD YOU TWICE, THIS IS A BAR. WE DON'T SELL FISH. IF YOU ASK AGAIN, I'M GONNA NAIL YOUR WEBBED FEET TO THE FLOOR!" The next day, the duck goes into the bar and asks, "Got any nails?" The bartender sighs and says, "No, we don't have any nails." The duck says, "Good. Got any fish?"