Screenwriter Leo Rosten pulled everything together for us when he said, “I cannot believe that the purpose of life is to be happy. I think the purpose of life is to be useful, to be responsible, to be compassionate. It is, above all, to matter, to count, to stand for something, to have made some difference that you lived at all.” Live with Purpose, Live by Priority, and Live for Productivity. Follow these three for the same reason you make the three commitments and avoid the four thieves—because you want to leave your mark. You want your life to matter.