The thing I love about this is that it doesn't even need to apply to the physical. Yes, my thing could be completing a marathon or climbing a mountain, but it could also be changing my major or moving across the world. I could make them all gasp, one day.
Wow - I love this! It just about summarizes it for me. I had a different view on how my life would be career wise but I can't complain. I have found great success and a profitable job, hobby, a new business venture that continues to expand. I can continue with this or always fall back on the career I love. Live the moment, take chances because something good can be awaiting you. :)