The so-called law is usually expressed as ‘If anything can go wrong, it will’.

Murphy’s Law parallels two other common terms for what is essentially the same pessimistic idea – Sod’s Law and Finagle’s Law. Of these three, Murphy’s Law is by far the more commonly used. The notion that ‘if anything can go wrong, it will’ is the simplest version of a notion that has been expressed in numerous ways. Many of these pre-date ‘Murphy’:

– Once a job is botched, any attempts to fix it make it worse.
– Bread always falls buttered side down.
– Whatever can go wrong will go wrong, and at the worst possible time, in the worst possible way.