My wife used to do deskside support.
I'll let my wife type the story, it's rather long:
I was hired into the IT dept. the first week I started college. I had the luck to have a member of the IT Dept staff as one of my professors who recognized I knew more about computers then some of the staff.
After I had been working for several weeks I had a ticket to install a new computer for the Chancellors administrative assistant. I'll date myself by stating it was a brand new IBM model 40 running OS/2.

In any case, I called her and made an appointment and at the appointed time showed up at her office with it.
For some reason, even though we spoke on the phone earlier she freaked out on me, stating "I WILL NOT let a student assistant install MY new computer that I have been waiting for 6 weeks for...blah blah blah and I know more about computers than you..." So I said, "Fine, set it up yourself. Call me when you need your old one picked up."
An hour later, she left me a miserable voice mail that it wouldn't power on and she couldn't understand why and would I come take a look at it. 3 hours later I bothered to stop by. I made sure everything was properly attached, after confirming that I crawled under her desk to check power and started laughing. She had plugged the surge strip back into itself. It gets worse. When I went to plug it into the wall she yelled at me, "What are you doing?! If you plug that into the wall my computer won't be protected from surges." I laughed, walked out, and called my manager, who also laughed.