?The only true way is to marshal the ferocity of your ambition over the course of many days, weeks, months, and (if you could finally come to accept it) years. The Trial of Miles; Miles of Trials? (12).
This quote is the key. I used it in some scholarship applications essays a few years ago, trying to explain how the lessons learned in running apply to life in general.
The thing is, everybody wants to be a winner. And when you're psyched up, you're willing to make any sacrifice. After a great workout, you'll happily go hit the weight room, or add extra miles, or eat spinach and broccoli. But what will you do when you're feeling like crap, or all your friends are going out, or it's pouring rain, or you're running poorly? To keep striving over the course of years, you need to smooth out the natural highs and lows of your desire, so that you have a constant and unrelenting force that drives you off the sofa and out to run. Every day. Twice.