Everything takes longer than you expect. Murphy seems to have suggested some corollaries to his law. One is that everything you decide to do costs more than first estimated. Another is that if you improve or tinker with something long enough, eventually it will break.
Mercy has a direct relationship to misery.
Nobody seems to know exactly who Murphy was, but whoever he was, he did not seem to know much about God's mercy. Murphy is not alone. Few people understand mercy. I have asked that question of a number of people and the most common response I get is a blank stare. The word is used literally hundreds of times in the Bible, and most of us have read it over and over again.