I had a fun one. In one corner of my basement - where I wanted to put my office - I had a big problem. With CRT computer monitors... the image would SHAKE badly. Like shimmy side to side, as if there was some huge magnet nearby trying to degauss it.

I ended up rotating my office with the monitor 180 degrees the other way, about 12 feet from the same spot, where the problem was about 85% reduced. However, I then discovered that if I ran a refresh rate of 85hz or higher, the unstable image would steady up and not shake.

Thankfully not a problem with LCDs!