[rphv]

Humans are evolutionarily optimized to do this. Add this to the long list of behaviors which were once beneficial from a survival standpoint but are now detrimental to our health - e.g. tribalism, shortsightedness, an insatiable taste for fats and sugars.

"The human species can change its own nature. What will it choose? Will it remain the same, teetering on a jerrybuilt foundation of partly obsolete Ice Age adaptations? Or will it press on toward still higher intelligence and creativity ...?" - E.O. Wilson "On Human Nature"