when is it time?

I am just now remembering that one time I was hanging out with my friend and I suddenly asked him: "would you rather die when you've finally reached that point where you're completely satisfied with your life or when you feel like you're in the darkest part of your life". I'm not sure what brought upon this question but my answer was not hard to arrive at. There are many reason why I would choose the first of the two, some unexplainable. Even as a child, I was always motivated by success not failure. This still holds true today. I want to live until I can say that I have accomplished every realistic goal that I ever wanted to accomplish. I want to die when I'm old and happy. I mean, isn't that why we work so hard in life? We  strive to eventually reach that happy place even if it means passing some hard times.