Work
In the hunting gathering days, there was no reason to work more than the 10-15 hours a week you needed to do to secure food. Overkill was punished because the food would rot before it could be eaten, and decrease food available to you in the environment in the future.
James Dale Davidson • The Sovereign Individual: How to Survive and Thrive During the Collapse of the Welfare State
many hard-to-explain animal traits and behaviors may well have been shaped by the seasonal over-abundance of energy rather than the battle for scarce resources, and that in this may lie a clue as to why we, the most energy-profligate of all species, work so hard.