After a French wedding the groom and his father and grandfather are having a nightcap in the bar before retiring, and bragging about their coming performance in bed. They agree that next morning they will let the others know how well they performed by how many times they say 'Bonjour' when they come down to breakfast next morning.
At breakfast, the groom arrives and addresses the room: 'Bonjour, Bonjour, Bonjour, Bonjour, Bonjour...'.
Next, his father comes in - 'Bonjour. Bonjour'.
Finally the grandfather comes in, smiles at the room full of friends and relatives and says 'Bon appetit.'