Murphy’s law?
This so-called ‘law’ says that ‘Anything that can go wrong will go wrong’.
The ‘Murphy’ in the expression is commonly believed to be a certain Captain Edward A. Murphy, who was an American aerospace engineer back in 1949.
During experiments, Murphy, whose relationship with his research team was not as good as it could have been, often used to complain that ‘if things could be done wrongly, they would be’.
It wasn’t long before the team members started referring to this idea as ‘Murphy’s Law’!
Example: "What can go wrong will go wrong - that's Murphy's Law!"