Murphy's law
expressionops culture
'Anything that can go wrong will go wrong' - engineering's oldest planning assumption.
The name traces to Captain Edward Murphy and the 1949 rocket-sled tests at Edwards Air Force Base, though participants told conflicting versions of who said what, and the sentiment predates them all. In operations it is not pessimism but method: design for the failure mode, because given enough deployments it will occur. Every redundancy, backup, and chaos drill is Murphy's law taken seriously.