I hope that this doesn't sound too self-centered, but you get to an age and notice that the people that obituaries are starting to be about people who are younger than you. Tony Snow faced the monster that was eating him a piece at a time, and he laughed with the joy of the life that remained:
Tony Snow in The Jewish World Review, 2005:
The art of being sick is not the same as the art of getting well. Some cancer patients recover; some don't. But the ordeal of facing your mortality and feeling your frailty sharpens your perspective about life. You appreciate little things more ferociously. You grasp the mystical power of love. You feel the gravitational pull of faith. And you realize you have received a unique gift – a field of vision others don't have about the power of hope and the limits of fear; a firm set of convictions about what really matters and what does not. You also feel obliged to share these insights – the most important of which is this: There are things far worse than illness – for instance, soullessness.