AC is AC and DC is DC

Me: You know how to measure AC current, right?
Tech: Yeah
Me: You just turn the knob to AC, OK?
Tech: OK
Me: The you put the probes and switch on, OK
Tech: OK.

Days later.....

Me: Can I borrow your meter, please?
Tech: Er, cannot.
Me: Why not?
Tech: Broken
Me: Why broken?

Tech hands me the meter and I opened it up......

Me: You tested AC with the DC setting, didn't you?
Tech: .........
Me: Haih.......... (No eye see)