From my experience talking to people about their experiences with old people and computers, the anecdotes are usually pretty funny
but let's not exclude stupid young people too
my mother is a constant source of material, here's one i can remember:
I set up a wireless network so she could access files on her desktop from her laptop. i sat her down and showed her how to use it, then at the end she said "right, well, probably not gonna remember that" I just left it, sort of expected her to say that.
Then I got the inevitable call for help one day, showed her again. This time I wrote down the instructions on paper and stuck them to the wall next to the computer, I assumed that would be the end of it.
Then one day I get another call, still having problems. I say, "just follow the instructions" but she's still having issues so I have a look and she's putting her files in the wrong folder, so I explained the error and then made the shared folder the ONLY folder on the desktop, put it smack in the middle of the screen and named it PUT FILES HERE TO GET THEM ON YOUR LAPTOP
next day, "it's not bloody working again"