I had one user really wind me up years back. The company used Lotus Notes for their email (a nightmare story in itself) and something had corrupted her client. When I was unable to fix it straight away she insisted that my predecessor would have had this done in seconds, why was I being so slow, that kind of gumph.
Anyway, I told her I had to double check a few things on the server and that I'd be back in 10 minutes. Got back to find the PC lying on the desk, open case, hard drive hanging out and a crowd of senior management around the desk. I immediately received a grilling - why did I leave her PC in such a state? Where have I been?
After a few moments I managed to explain that I hadn't done any of this and the lady eventually conceded that while I had started to look into the problem she had figured she could resolve this herself. Turns out my predecessor's last visit to her PC had involved him replacing a faulty hard drive. She had watched him unplug and plug the HDD back in again and hey presto - the PC worked again. Surely thats all it took for her to fix the problem, right?
When other people stopped by to see her with her PC in such a state she had opened with, "Oh its IT's fault, they're messing up my PC trying to fix it".