Here are a few theories;
Christine Frankland: Life is just a blank slate, what matters most is what you write on it.
City Slickers (movie)
Curly Washburn: Do you know what the secret of life is?
[holds up one finger] This.
Mitch Robbins: Your finger?
Curly: One thing. Just one thing. You stick to that and the rest don't mean sh#@.
Mitch: But, what is the "one thing?"
Curly: That's what *you* have to find out.
Cherokee saying: When you were born, you cried and the world rejoiced. Live your life so that when you die, the world cries and you rejoice.
Andy Dufresne (Shawshank Redemption - movie): Get busy living, or get busy dying.