Our expensive PCs
People get used to consumer grade PCs with cheapo power supplies where you just plug in the mains cable and off you go. Our expensive "enterprise grade" boxes though have a not-very-visible rocker switch that you also have to turn on. Gets 'em every time.
I have to say I have given up being snarky with un-knowledgeable users. I used to get all frustrated about them "wasting my time" but what is the point.