I do agree this is good advice:

I got two pieces of advice I have always remembered. The first was from my father, Charles E. Murphy, who was a justice of the New York State Supreme Court. It was a point about ethics. He said, "Doing the wrong thing is not worth the loss of one night's good sleep."

The other came from Benjamin Selekman, a Harvard Business School professor who taught labor relations. The last thing he said, at his last lecture to my class, was, "Here is something to remember for the rest of your life: Don't spend your time on things you can't control. Instead, spend your time thinking about what you can.

- Thomas S. Murphy, Former CEO, Capital Cities/ABC