Why on earth would anyone want to run 50 miles? It's a fair question.
I don't have a good answer.
I do know, however, that some of the most enjoyable parts of my week occur early in the early morning as I run up the ridgeline in the day's first light. I have yet to dread my long training runs and the chronic tight achiless tendons and achy knees that I was experiencing have faded. My body is adapting and getting stronger.
David Horton suggests that completing an ultra can be the most "rewarding, enjoyable, exciting, and fullfilling moment" of one's athletic career. He says, "before your first ultra you should announce to everyone that you know what you are doing to hold yourself accountable" and relates that many ultra runners are ordinary people doing extraordinary things. He suggests that one must have "desire, discipline, and dedication" to train for and succeed at finishing an ultra and that the enjoyment and excitement of completing the race will make the effort worthwhile.