Our days are numbered. At this very moment, many thousands are born into the world, some destined to live only a few days or weeks, and then tragically succumb to illness or other misfortune. Others are destined to push through to the century mark, perhaps even a bit beyond, and savor every taste life has to offer: triumph, despair, joy, hatred, and love. We never know. But whether we live a day or a century, a central question always remains: What is the purpose of our life? What makes our lives meaningful? ...

— Dalai Lama

from The Art of Happiness