A new customer walks into the new store on the block that sells brains. There are three glass cases, each containing a nice wet quivering grey brain.
The first one says "Astrophysicist", and it costs $10. The second says "Avon Salesman" and costs $1000. The third says "Drummer" and costs $10,000.
The customer is confused, and questions the salesperson. "I don’t get it…why would I want a drummer’s brain for $10,000 when I can get an astrophysicists’ for $10?".
The salesman replies, "Because it’s never been used."