Customer: My keyboard is not working anymore.

Tech support: Are you sure it's plugged into the computer?

Customer: No. I can't get behind the computer.

Tech support: Pick up your keyboard and walk 10 paces back.

Customer: OK

Tech support: Did the keyboard come with you?

Customer: Yes

Tech support: That means the keyboard is not plugged in. Is there another keyboard?

Customer: Yes, there's another one here. Ah...that one does work