So, a duck walks into a bar, takes a look around, walks up to the bartender and asks, "Do you have any crackers?" The bartender says no, and the duck leaves.
The next day, the duck walks back into the bar, goes up to the bartender again and says, "Excuse me, do you have any crackers today?" The bartender looks up, and with an impatient shake of his head says, "I told you yesterday, we don't have any crackers." The duck turns and leaves.
The next day, the duck walks back into the bar, goes up to the bartender again and once more asks, "Do you have any crackers?" The bartender, annoyed, grabs the duck by the neck and says, "Look, I told you before, we don't have any crackers. And if you come back here again, I'll nail your freakin' bill to the bar." The duck leaves.
The next day, the duck walks back into the bar, goes up to the bartender again and says, "Excuse me, but do you have any nails?" The bartender screams, "NO!" So, the duck says, "Great. Do you have any crackers?"