One of the main consequences after Smith's theory (which later would become the basis of modern and classic economics) is that we get the best of our society if we seek our sole individual benefit while competing with each other. After's Nash Game Theory, this statement did not hold anymore. Altruistic behavior has been perfectly correlated to intelligence and this makes perfect sense, evolution seems to reward cooperating and altruistic conduct. Moreover, even babies are able to identify 'mean' actors and are more likely to pick the "good" one over the bully. It's just beautiful: be nice and forgiving is a strategy that stands out in a lot of scenarios. Take a moment to appreciate how inspiring and optimistic that is.
