quite an old one this, not sure if already posted:
A duck walks into a bar and asks the barman for a bowl of grapes. The barman said that he did not have any grapes unfortuantely so the duck says that's a shame and toddles off out.
The following day the duck comes in again and asks for a bowl of grapes again. The barman says again he does not and that he doesn't ever have any in so to try elsewhere in future. The duck again leaves without any issue.
Again the the following day the duck comes in, the landlord is getting a bit angry at this point, thinking, why is he here again?! The duck, again asks if he has any grapes. Unsurprisingly he doesn't and this time raises his voice, he's very busy, lots of people in eating and drinking and this is not helping. He shouts at the duck saying 'look son, we don't have any effing grapes, we never will, and if you come in here again wasting my time again to ask I will nail yer bloody beak to the bar, do you hear me?' The duck again calmly leaves the pub unperturbed.
The next day the duck comes in, same time, pub just as busy. He approaches the bar, the barman's blood is boiling as he sees him walking in. The duck, calm as ever, today asks the barman, 'hi there, do you have any nails?'
'NAILS, NAILS, NO I DON'T HAVE ANY BLOODY NAILS, WHY WOULD I HAVE NAILS, THIS IS A PUB!!'
'Lovely,' the duck replies, 'so, do you have any grapes?'