…we assume that people naturally avoid challenging themselves, that it is “human nature” to be lazy. The evidence shows that if anything deserves to be called natural, it is the tendency to seek out optimal challenge, to struggle to make sense of the world, to fool around with unfamiliar ideas.

-Alfie Kohn, from Punished by Rewards: The Trouble with Gold Stars, Incentive Plans, A’s, Praise, and Other Bribes