concept
Murphy's Law
Anything that can go wrong, will.
Origin
Named for Edward Murphy, an Air Force engineer who, after a 1949 rocket-sled test had been wired incorrectly, complained that if there were a way to do something wrong, somebody would find it. Colleagues rephrased it and adopted it as a design discipline: assume the worst arrangement is possible and prevent it by construction.
Modern usage
Universally invoked to explain โ usually after the fact โ why the demo broke, the flight was delayed, or the wedding rained. The serious engineering meaning (design for failure) is mostly forgotten.
In the wild
Murphy's Law: the bug shows up only in the live demo.โ engineering folklore
Tags
pessimism
engineering
law