A duck walks into a bar and asks the bartender: "do you have any bread" when the bartender replies "no" he leaves the bar, dissapointed.

15minutes the duck returns and asks the bartender again "do you have any bread?" he gets the same reply and once again leaves, dissapointed and empty handed.

After a 3rd and 4th time of entering and asking for bread the bartender loses it and shouts, "listen, if you come in here asking for bread one more time im going to nail your beak to the counter!". The duck leaves.

30 mins later the duck comes back and asks the bartender "do you have any nails?" when the bartender replies "no" the duck proceeds, "ok, do you have any bread?"=)