Funny Joke

A duck walks into a store and asks the manager if he sells grapes. The manager says no, so the duck leaves. The next day the duck goes back to the same store and asks the manager if he sells grapes. The manager says,"NO, we do not sell grapes,"so the duck leaves the store. The next day the duck goes back to the same store and asks the manager if he sells grapes. The manager is furious now and says,"NO, WE DO NOT SELL GRAPES! IF YOU COME BACK AND ASK IF WE SELL GRAPES AGAIN, I WILL NAIL YOUR BEAK TO THE FLOOR! The next day the duck goes back to the same store and says to the manager,"Excuse me, do you sell nails at this store?" The manager says,"no, we don't sell nails." The duck replies,"That's good. Do you sell grapes?"