I think this is very similar to the reason of why I like the novel so much. It is about the human condition that most of us grapple with at some point in our lives. When age takes its toll on our body, mind, and spirit is there redemption to be found in perhaps one final heroic act? In the end Santaiago is a man who finds some redemption but it is tempered by life's often cruel balancing act. Santiago brings the great marlin in but not before it is eaten by sharks. This perhaps is the ultimate metaphor and irony of life.