A couple of days ago, the printer jammed in our office. This is no surprise, because it's an all-in-one unit (basically a Canon copier that's also a networked printer and scanner) and such are specially designed to keep repairmen in employment by breaking as often as possible.
A colleague found the jam and removed the offending bit of paper, but the display on the printer still said: "Paper jam: open cover and clear jam". No amount of pressing "Cancel" or "OK", or opening and closing doors and drawers, would make this message go away.
And then the statement came, from one of the non-techies sitting nearby.
"Oh, it does that. You have to turn it off and back on again".
Looks like our secret is out ...