This lesson came via the latest Mars Hill Audio Journal, Volume 110, which I listened to on the way to Berkeley. Ken Myers interviewed Kevin Belmonte, author of two recent books on G. K. Chesterton. These are Defiant Joy: The Remarkable Life and Impact of G. K. Chesterton, and The Quotable Chesterton: The Wit and Wisdom of G. K. Chesterton.
"The perfect happiness of men on earth (if it ever comes) will not be a flat and solid thing like the satisfaction of animals. It will be an exact and perilous balance; like that of a desperate romance. Man must have just enough faith in himself to have adventures, and just enough doubt of himself to enjoy them."
I'll sum this long entry up with one more Chesterton quotation. It is about the joy of fighting for what's right: "The full value of this life can only be found by fighting; the violent take it by storm. And if we have accepted everything we have missed something--war. This life of ours is a very enjoyable fight, but a very miserable truce."