Somewhat joking, BUT it's true. The easiest way to fix a problem, especially a networking problems is to pull plugs, wait for a few minutes and plug them back in.
Honestly, I wish I understood networking -- this morning I came in and my lab was completely down. Most of the workstations could not communicate with the server and even said "network connectivity is low or limited". I couldn't see the other workstations with Lanschool. It was a mess.
At first, I thought the whole building was down, but I isolated it this end of the building pretty quick. In fact, once I got students in the room, I isolated it to the students on the older switches in the classroom. All I had to do was unplug them and plug them back in and the network started working again. Thus "Weaver's Law".
Yeah, it probably already exists under another name, but it works for me.