Great post and great read. Some really valid points! Speaking from a naive 20's something perspective I feel as though all stages of life present great challenges and obstacles. However the challenges for youth is finding ones 'why.' What do yo want to do with your life. This may change with time but not usually drastically unless some major paradigm shifts occur. At the same time the positive is there is so much time to achieve all of these goals.
From what I have seen, the challenge of reaching an elderly age is, those who do not chase their 'why' usually become pessimistic, bitter and regretful individuals. As opposed to those who have lived an enriching, meaningful and satisfying life of continuously improving oneself and learning. These people are perhaps some of the happiest individuals that I have ever encountered.