So I'm an IT consultant, and one of my clients is having a problem with accessing a printer over the network; I run through the usual - reboot the printer, reboot the computer, etc. Nothing helps.
Me: "Just out of curiosity, are there any lights on on the front of the printer?"
Them: "Just the one that says pause."
Me: "..." *facepalm* "Press the button next to Pause."
Them: "Oh, it works now."