The corollary here is that the harder something is to get at or repair, the more likely that it will fail at an inopportune moment.
Adams on Murphy. Adams on Murphy —
“The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair.”
— Douglas Adams (1952 – 2001), Mostly Harmless