Quote attributed to BF Skinner (via Sam Carpenter and Mathew Strong):
When people work only to avoid losing a job, study only to avoid failure, and treat each other well only to avoid censure or institutional punishment, the threatening contingencies generalize. It always seems as if there must be something that one ought to be doing. As a result very few people can simply do nothing. They can relax only with the help of sedatives or tranquilizers, or by deliberately practicing relaxation. They can sleep only with the help of sleeping pills, of which billions are sold in the West every year. They are puzzled by, and envy, those in less developed countries whom they see happily doing nothing.
Moral to the story: don’t work for avoidance — work in favor of positive things. And learn to relax.