Principles are ways of successfully dealing with reality to get what you want out of life.
Ray Dalio, one of the world’s most successful investors and entrepreneurs, cites principles as his key to success.
Don't assume that people are operating in your interest rather than their own. A higher percentage of the population than you might imagine will cheat if given the opportunity. When offered the choice of being fair with you or taking more for themselves, most people will take more for themselves. Even a tiny amount of cheating is intolerable, so your happiness and success will depend on your controls. I have repeatedly learned this lesson the hard way.