"Adaptation is, in part, just a property of neurons: Nerve cells respond vigorously to new stimuli, but gradually they 'habituate,' firing less to stimuli that they have become used to. It is change that contains vital information, not steady states. Human beings, however, take adaptation to cognitive extremes. We don't just habituate, we recalibrate. We create for ourselves a world of targets, and each time we hit one we replace it with another. After a string of successes we aim higher; after a massive setback, such as a broken neck, we aim lower. Instead of following Buddhist and Stoic advice to surrender attachments and let events happen, we surround ourselves with goals, hopes, and expectations, and then feel pleasure and pain in relation to our progress." Jonathan Haidt