I used to work for an IT helpdesk. That means I've seen far more than my share of operator error. Operator error is, for purposes of this post, whenever someone has broken his/her computer through his/her actions and not through a problem with the software or hardware. So, if someone's network cable comes unplugged, that's not operator error. But when someone puts an unconventionally shaped CD into a CD player and it gets stuck, that's operator error.
One of my favorite stories involves doing phone support. I was on the phone with these very sweet and not at all technically inclined women. They needed to reboot the server. Now, servers don't have nice big fat power buttons. And this model required you to hold the power button down for a few seconds. So I talk them through (and yes, I was talking to 3 women at the same time) unlocking and opening the front faceplate of the server. Then I tell them to find the small button (black on a black background) and hold it down. Nothing happened. Repeatedly. I'm asking and asking and asking for confirmation, and nothing is happening. Finally, one of the women says, "What about the tray?"
"What tray?" I ask. "There's a tray that keeps coming in and out."
And that was when I realized they had been pressing the CD eject button. For 10 minutes. While telling me that nothing was happening when they pressed the button.
And that, folks, is operator error!