Dad: I want you to marry a girl of my choice
Son: I will choose my own bride.
Dad: But the girl is Bill Gates's daughter.
Son: Well, in that case...ok.

Next Dad approaches Bill Gates.
Dad: I have a husband for your daughter.
Bill Gates: But my daughter is too young to marry!
Dad: But this young man is a vice-president of the World Bank.
Bill Gates: Ah, in that case...ok.

Finally Dad goes to see the president of the World Bank
Dad: I have a young man to be recommended as a vice-president.
President: But I already have more vice-presidents than I need!
Dad: But this young man is Bill Gates's son-in-law.
President: Ah, in that case...ok