The hard part about making things idiot proof is that idiots can be so ingenius sometimes when it comes to ways of screwing up. I remember a funny line about programming by Rich Cook:

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."

Still, there's no good excuse for designing things so that connectors can be put together incorrectly. Likewise, everything breaks eventually, so things like long duration manned spacecraft must be designed to be maintained and repaired in flight, perhaps by crewmembers who're wearing gloves. Kim Keller used to write about how difficult it was to work on the Shuttle. It was a 1970s design that was optimized for spaceflight, not maintenance. Working on them were a real pain in the ass.

Years ago, I read an article in an Air Force magazine about a program to get engineers from aerospace companies to go out on flight lines to see how their products had to be maintained. They got an earful, especially from the line crew who had to work outside during the winter at places like Minot AFB, SD ("Why not Minot? Freezin' the reason.") Even seemingly simple repair jobs become a real challenge at 30 below zero, especially when cramped spaces make you take off your gloves. They especially had harsh words for safety wire. The program was wildly popular with both the engineers and the maintenance crews. No doubt, it was probably canceled. It made too much sense.