I will live this day as if it is my last. And what shall I do with this last precious day which remains in my keeping? I will waste not a moment mourning yesterday's misfortunes, defeats or heartaches, for why should I throw good after bad?

I have but one life and life is naught but a measurement of time. When I waste one I destroy the other. If I waste today I destroy the last page of my life. Therefore, each hour of this day will I cherish for it can never return.

Og Mandino, The Greatest Salesman in the World