Client: I just put in your CD, but I still see my previous CD on the computer. I can’t access your CD!
Me: Can you open your CD drive and verify that it is my disk that you’re using?
Client: I’m not stupid!
Me: I’m not saying you are, but can you double check for me?
He does, and (less than kindly) says my CD is staring back at him.
Client: Maybe you’re the stupid one and you forgot to put anything on it.
Me: Can you check the bottom of the CD? It should have rings if it’s been written on.
Turns out he placed my CD on top of his and then just closed the CD drive.