Dad: What is that?
Son: It's a ship.
Dad: What is that?
Son: It's a boat.
Dad: What is the difference between a ship and a boat?
Son: You can put a boat on a ship but not a ship on a boat.
This Q&A goes on for some time till they are walking back to the car.
Son: What is that?
Dad: That, my boy, is a beautiful brunette.
Son: And what is that?
Dad: Ahhh, that's a blond.
Son: What is the difference between a brunette and a blond?
Dad: A brunette is sensible, forceful, organised, has her own mind and knows about money. A blond, she knows how to make a man happy.
Son: Dad, mum's not a natural blond, is she?