"Mechanical Sympathy" and magic
In some people's eyes, I am a 'tech magician' (admitting this will probably make my powers vanish through the mechanism of hubris, but we'll see) - many times I've heard swearing coming from a relative or colleague because they couldn't do something on their computer; they finally ask me to help, and I turn up, and just by standing there suddenly everything works. Sometimes I have to sit down and 'do exactly the same as they were doing'.
My suspicion is that it has something to do with 'mechanical sympathy': my knowledge of the underlying technology and the way in which the user interface developer was thinking helps. People don't help themselves by double-clicking everything; leaving CAPS LOCK on, pressing '(Carriage)Return' to move between fields in a dialogue box instead of 'Tab' etc.
In the same way that some people understand how cars work, so don't treat the accelerator as a binary control; brake smoothly and progressively and not jerkily at the last minute; turn the steering wheel while the road wheels are turning; and not relying on power-steering to scrub the wheels round when stationary etc I think some people have a knack for using IT well, and others do the equivalent of crashing the gears.
So when I turn up, just the mere fact of me standing by them makes them take that little bit more care, and suddenly things work. It isn't magic: but some people prefer to think that than question their own competence at using their own computer.