Wondering: what was the craziest snafu you've been presented with?
I was called in to debug a signal mux/data acquisition monitor fixture that had several PC-sized units interconnected with a boatload of cables and connectors between them. It wasn't completely dead, but nothing it did made much sense.
When I started digging into the issue, I found that their schematics had a number of wiring mismatches (between the schematics themselves). Pressure sensor A in one box, accidentally & supposedly became Temperature sensor A in another box. Apparently their tech had raised the issue during construction, but was told it would be taken care of later & he should concern himself with just building what he was given. However, that was only the beginning of the madness. Some circuit boards layouts had some of their connectors mirrored. In some cases this was "ok" since the other cable end had accidentally been mirrored as well. But tapping into the cable itself for a reading would give the wrong information. Others had the physical circular connectors rotated off by one pin count. Making my way through this maze (thanks a lot for using all the same color wires), was quite an adventure. Luckily no damage was done by all of this. It finally came together, after most of the original wiring was completely trashed.