I was having trouble with my computer. So I called Harold, the computer guy, to come over.
Harold clicked a couple of buttons and solved the problem. He gave me a bill for a minimum service call.
As he was walking away, I called after him, "So what was wrong?"
He replied, "It was an ID ten T error."
I didn't want to appear stupid, but I nonetheless inquired, "An ID ten T error? what's that, in case I need to fix it again?"
"Write it down, I think you will figure it out." Harold said.
So I wrote it down: ID10T
I used to like Harold...