“The formulation of the theory of samsara or rebirth is no proof that the Upanishads are pessimistic. Life on earth is the means of self-perfection. We have to undergo the discipline of samsara in our efforts towards the higher joy and the complete possession of spiritual truth. That which gives zest to life is the supreme motive of the joy of self-conquest. Samsara is only a succession of spiritual opportunities. Life is a stage in spiritual perfection, a step in the passage to the infinite.”
An aim in life of perfecting the soul gives zest to our actions, even in old age. Most people, even as they are near death, know that they are unfinished works. Hence the idea of samsara, reincarnation, or in the Catholic tradition, purgatory. We need more perfecting.