Once I went to repair a customers "Faulty" fax machine.
The little old lady explained that every time she put a letter into the send slot it kept falling out from a crack in the cover.
I had to explain that the machine did not actually transmit the envelope with the letter inside to her son but an image of the text on the sheet of paper. 
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Once I had to drive from Manchester to Inverness (360 miles) to repair a "Faulty" copier.
The customer explained that the machine was dead. It had been working the previous week but now it would not turn on.
When I looked at the machine I couldn't find the mains cable, I asked the customer where it was, she told me she was using it for the kettle because it was longer than the original.
I had to point out that the machine had to be connected to the mains for it to work. 
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Once I was called out to repair a "faulty" laser printer.
I was told that they had returned 4 previous printers back to the manufacturer because they had only worked for a month before breaking down.
The customer wanted to know why the printers were so unreliable and would not let me go until he had a satisfactory explanation.
I showed him the page in the user manual which explained about replacing the toner cartridge (ink) when it runs out. 
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Once I had to do a repair at sellafield nuclear power station.
When I arrived at the main gate I was asked for some personal identification (driving license), they then contacted my employer to verify my identity.
I then had my photograph taken and a visitors pass created for that day.
I then had to watch a video about the dangers of the site and what to do in an emergency.
I had to take every thing out of my van to enable security to search every thing and was eventually escorted to the location of the faulty copier after about 2 1/2 hours after my arrival.
Unfortunately I did not have the required part on my car stock so had to arrange for the part to be posted to site.
A couple of days later I once again arrived at the power plant to fit the part but I went to one of the closest side entrances.
The security guy just pointed in the general direction and said "it's over there" and went back to reading his newspaper.
It's nice to know that one of the top terrorists targets is well protected.
Providing they try to get in though the main gate. 