Life of Pi, by Yann Martel

Life on a lifeboat isn't much of a life. It is like an end game in chess, a game with few pieces. The elements couldn't be more simple, nor the stakes higher. Physically it is extraordinarily arduous, and morally it is killing. You make adjustments if you want to survive. Much becomes expendable. You get your happiness where you can. You reach a point where you're at the bottom of hell, yet you have your arms crossed and a smile on your face, and you feel you're the luckiest person on earth. Why? Because at your feet you have a tiny dead fish.