A duck walks into a convenience store and asks the clerk, "Got any Grapes?"  Clerk looks at him and says, "We don't sell grapes here this a convenience store."  The duck turns around and walks out of the convenience store.  An hour later the duck comes back and walks up to the clerk, "Got any grapes?"  The Clerk says, "I told you before this a convenience store we don't sell any grapes."  So the duck walks back out.  An hour later the duck comes back and asks, "Got any grapes?"   The clerk frustrated tells the duck, "I told you before this is a convenience store, and we don't sell any grapes.  If you come back again I'm going to nail you to the floor and slap you silly."  The duck turns and walks back out.  An hour later the duck returns and walks up to the clerk, "Got any nails?",  The clerk say's "No", "Got any Grapes?"