Murphy's Law, often rendered as "If anything can go wrong, it will." was named after Captain Edward A. Murphy, an engineer. It seems rather negative but in fact it's a central tenet of "defensive design" a design methodology in which engineers attempt to make idiot-proof systems.
Murphy's Law inspires a whole host of related laws, principles, corollaries, theories and clever sayings. Here, along with Murphy's formulation, are seven other classic Murphisms.