suck switch

Any random piece of hardware, software or even something hidden in firmware or the UI that is easily flipped, and no logical person would expect to force a system to stop working. And yet, it does. Making the system un-suck is usually much harder to find than the aforementioned switch.

"Why does my wifi no longer work? I can still reach it on my phone".
"Oh, there's a little switch on the side of your laptop that shuts it off. A lot of people hit it accidentally".
"Well, that's a suck switch!"