Vent: took me 3 hours to figure out my Switch dock was plugged into the TV's USB port, not the wall
My niece wanted to play Mario Kart 8 with me last Friday. I set up the dock, slid the console in, hit the power button on the pro controller. Nothing. Black screen. I checked the HDMI cable, swapped it twice. I reset the TV. I held the power button for 15 seconds like some forum said. I even dug out my old HDMI splitter from a box in the closet thinking the port was dead. My sister walks in, looks at the back of the TV for two seconds, and asks why the dock's USB cable is in the TV's service port. I moved it to the wall outlet and it turned on instantly. Three hours. For a cable in the wrong hole. She has not let me live it down. Anyone else ever lose an embarrassing amount of time to something this dumb?
Something like this happens to everyone at some point. I spent almost two hours once trying to get my laptop to charge, swapping cables and outlets, before I saw I had plugged the charger into itself instead of the wall. My roommate still brings it up at dinner. At least your sister found it fast, even if she won't let it go.