"Got any grapes?" he asks the bartender.
"Nope."
So the duck leaves.
The next day, the duck comes back.
"Got any grapes?" he asks.
"Nope," says the bartender.
The next day....the duck comes back again.
"Got any grapes?"
"Look, duck," says the bartender, "I didn't have any grapes yesterday, I don't have any today, and I'm not going to have any tomorrow. And if you come back here asking for grapes again, I'm gonna nail your feet to the bar."
The duck leaves....
The next day, the duck comes back.
He walks up to the bartender.
"Got any nails?"
"Nope."
"Got any grapes?"
:)