What is the effect of not using it, but not using it?

Murphy's Law is often used when not used.

Murphy's Law is a psychological effect, which was put forward by EdwardA.Murphy, also known as Murphy's Law and Murphy's Theorem. The original sentence of Murphy's Law is: If there are two or more ways to do something, and one of the choices will lead to disaster, someone will definitely make this choice. The basic content is: if things are likely to go bad, no matter how small the possibility is, it will always happen.