A man goes to the famous Lucas Carton restaurant in Paris with his girlfriend and orders the 1928 Mouton.
The waiter returns with a bottle full of wine, pours a small amount in the glass for tasting.
The customer picks up the glass, smells the wine, and puts it down on the table with a thud.
"This is not the 1928 Mouton."
The waiter assures him it is, and soon there are another twenty people surrounding the table, including the chef and the manager trying to convince the man that the wine is the 1928 Mouton. Finally someone asks him how he knows that it is not the 1928 Mouton.
"My name is Phillipe de Rothschild, and I make the wine."
Finally, the original waiter steps forward and admits that he poured the Clerc Milon 1928.
"I could not bear to part with our last bottle of 1928 Mouton. You know Clerc Milon, it is in the same village as Mouton, you pick the grapes at the same time, the same cepage, you crush in the same way, you put them into similar barrels. You bottle at the same time, you even use eggs from the same chickens to fine them. The wines are the same, except for a small matter of geographic location."
Rothschild beckons the waiter forward, and whispers to him,
"When you return home tonight, ask your girlfriend to remove her underwear. Put one finger in one opening, another finger in the other, then smell both the fingers. You will understand what difference a small distance in geographic location makes."