I am currently reading Running With The Kenyans by Adharanand Finn. I won't say much just now, I intend to write a longer writeup once I have finished. But for now I want to capture a quote from the book that I think is brilliantly accurate:
Running is like getting drunk in reverse. With drinking, it feels great at first, but the you start feeling awful. With running, you feel awful at first, but then, after you finish, you feel great.