The environment we're used to is designed to sustain us. We live like fish in an aquarium. Food comes mysteriously down, oxygen bubbles up. We are the domestic pets of a human zoo we call civilization. Then we go into nature, where we are least among equals with all other creatures. There we are put to the test. Most of us sleep through the test. We get in and out and never know what might have been demanded. Such an experience can make us even more vulnerable, for we come away with the illusion of growing hardy, salty, knowledgeable: Been there, done that. --Laurence Gonzales in Deep Survival, page 133.