I love these stories, it shows what a nasty, immature disfunctional bunch we are.
Back when I ran Helldesk , a mercifully brief contract covering for a mate who'd gone on to better things, I'd have written "PC" up for being a lazy .CNT and added him to my mental list of people to get rid of at the first opportunity.
Working the tech support phone you are the face of the company. You are also there to fucking help people (hint: the clue is in the name). The people calling need help and for many of them you are the only lifeline they have. They are probably already stressed enough from having to listen to our shitty hold music for ten minutes and they don't need you being a smartarse. It costs nothing to be helpful - even if that just means, in this case, working out that the file has gone missing and the caller needs to talk to someone else (bonus points for pointing him in the right direction) - and the whole company looks good and I get to add another successful resolution to our numbers. Enough of the latter (but not so many that the baseline gets pushed up, please) and we all get a bonus at the end of the year.
If you can't manage that then you should be looking for another line of work. Mocking people who are unfortunate enough to be in the position of relying on technology which is, to them, little short of black magic, says more about our insecurity than their ignorance.
OK, having said all that, the bloke I took over running that support desk from went on to run internal training. It was around the time that PCs were being dumped on C-level desks and I suspect someone in the company thought that if they could teach executives read and answer their own email then they could sack a few secretaries and PAs. My mate was the guy who did the teaching and his best story was the CFO who had got it into his head that you couldn't lift the mouse off the desk. Cue "click on blah", "it won't reach", etc.
I also don't get the calling people "sir" thing. I've never done it and never had it done to me. If someone on tech support did so, I'd probably assume they were taking the piss and tell them that the call will go a lot smoother is they drop the condescension. Every time I see it in story about a support call, it makes me think the story is made up by some 15 year old geek working as a junior salesman at whatever big box consumer electronics store blights your region.