Helpdesk muppets.
My favourites over the last couple of years working for the NHS:

1) Telling me to try rebooting, no matter what was wrong with my pooter. Including stuff like "the projector won't come on when I hit the power switch".

2) Due to him using the word "mate" as punctuation, having to say to the tech monkey "Look, I'm not your mate, will you stop calling me it?"

3) And this one happens a lot:
Me: Hi, I can't log into SystemX, when I click on the icon, I get an error saying "wibble flibble dibble not found"
IT blokey: Right, first can you log out of SystemX?

4) Since I work in System Support, I can see the calls that I have raised. 90% of the time, what is on the logging system bears no resemblance to what I've said. It's also amazing the amount of times I am assigned an issue, work out a resolution and ring the user, only to be told "that's not the problem I'm having, it doesn't surprise me though, the guy I spoke to wasn't paying attention when I explained it to him. And he called me 'Mate' a lot"

I also had a fantastically fun one:
Some of the users in my last place had my mobile number, so would ring me directly out of hours. I had the best call ever (and by "best" I mean "worst"): one of the theatre staff rang me and said "A patient has just died in recovery, but the nurse has logged them as having gone back to , how do we get them back on the system?". I walked them through it, then hung up and has a little cry... since it was 7am on the 25th of December. That was a very Merry Christmas for some poor mother.
(ScousersPet, Wed 30 Sep 2009, 16:07, 3 replies)

What year was this?
I used to work on the NHS CfH desk for Fujitsu some time ago. And I was never that bad.
( jim_bob can herd cats., Wed 30 Sep 2009, 16:11, closed)

Nah
It was always the local helpdesk I was dealing with. We don't even deal with Fujitsu on a national level anymore...
(ScousersPet, Thu 1 Oct 2009, 9:24, closed)

"Mate"
I know the feeling. Whilst I was working in the driving school years ago some obnoxious git of a customer strutted around the office using "bruv" as punctuation. The temptation to tell him, "Stop calling me 'bruv,' I am not your brother; in fact if I were to find out I was that closely related to you I'd commit suicide pretty sharpish," was almost as great as the temptation to twat him across the face with the desk.
(LongJohnBaldry, Thu 1 Oct 2009, 9:32, closed)