A small geographical difference

An elderly man walks in to the famous restaurant Lucas Carton in Paris with his girlfriend. He orders a bottle of Rothschild Mouton 1928.
The waiter returns with a full bottle of wine and fill up a small amount in a glass for tasting.
The man barely smells the wine before putting the glass down and stating: "This is not a 1928 Mouton!"

Soon, almost 20 people are standing around the table. This includes the chef and the restaurants owner. Every single one is trying to convince the old man that it is, in fact, a 1928 Mouton. The waiter then asks: "How can you be so sure this *isn't* a 1928 Mouton?"

The elderly man then states: "My name is Phillip de Rothschild, and I produce this wine!"
The waiter then admits that the wine actually is a Clerc Milon 1928. "I could not bear the thought of us parting with the last bottle of Mouton 1928. You know, Clerc Milon is produced in the exact same village, with the exact same grapes, the same type of baskets and aged in the exact same barrels. The wines are *exactly* the same, the only difference is that the vineyards are on the other side of the village."

Rotschild turns to the waiter and says: "When you get home tonight, ask your wife to undress, and put one finger in each hole. Pull them out, and smell them. You'll then understand the importance of a small geographical difference."