At one point, I encountered a low level bug that would only manifest if the computer was physically located in a particular room. It ended up being an undocumented cabling revision, but I revisited a lot of assumptions about the nature of software and reality before getting to that point.
I have come to love the feeling that the universe is broken when bug hunting. It means the solution is close at hand. If there are still lots of plausible explanations left then it means there is lots of work left to do. Things always seem most insane just before figuring it out.
"but I revisited a lot of assumptions about the nature of software and reality before getting to that point."
I encountered some bugs that felt like this (software only though), where I did not found the all explaining logical solution and ended up rewriting that part.
But I saved the whole state of the project and data in a zipped file and keep them locked away - so one day, when I feel like madness (and maybe have better tools avaiable) I will jump into it, either to proof my own stupidity - or the existence of dark magic, poltergeister and demons.
