A couple goes to a fair every year. And, every year, the man wants to ride an airplane.
The wife says, "We've talked about this. £20 is £20."
A pilot overhears their conversation and tells them, "I will make you a deal. I will take you up in the plane. And if you do not say a word, it is free. If you say one word, it is £20."
They get in, and he goes up, and does loops and dives - the man says nothing.
When they land, the pilot says, "Wow, I was sure you would say something."
The man replies, "Well, I did think about it when my wife fell out, but £20 is £20."