A guy i worked with called me over to try to help him figure out why his apple wireless mouse wasn’t working. I replace the batteries, restarted bluetooth, restarted the computer - i’d spent quite a bit of time working thru my mental checklist when the guy just started moving the mouse furiously, as if he expected that would re-animate it, and the cursor. It didn’t. But out of the corner of my eye i noticed the cursor moving on a screen two desks away, a desk whose occupant was out to lunch. I asked the inevitable question and the guy admitted that his mouse had stopped working, figured the batteries had run out (they had) and he was in a hurry so he grabbed somebody else’s mouse instead. To this day i don't know whether i’m more flabbergasted that he omitted to mention this when he first called me over, or that he thought the act of placing a mouse in front of his computer was all it took for the pair to communicate.