A duck walks into a bar, hops on a barstool, and asks the barkeep, "Got any grapes?"
"Grapes? We don't have grapes, just booze and peanuts."
"Oh," says the duck, disappointed, and he leaves. The next day, he's back in the bar. He hops up on a barstool and asks the barkeep, "Got any grapes?"
"Hey, weren't you in here yesterday? I told you, we don't got any grapes! Now scram!"
Obligingly, the duck scrams, but the next day, he's in the bar again. He jumps onto a barstool and, predictably, asks the long-suffering barkeep, "Got any grapes?"
"No!" shouts the barkeep. "We don't have any grapes! This is not a supermarket! If you come in here and ask for grapes one more time, I'll nail your little beak to the bar! Now get your feathered tail out of here!"
The duck leaves, but the next day he walks back into the bar and hops onto a barstool. The barkeep spots him and his cheeks start to turn red, but before he can say anything the duck pipes up, "Got any nails?"
"Now it's nails!" cries the barkeep. "NO, we don't have any nails!"
"Oh good," says the duck. "Got any grapes?"