Some of us have big brains. There's a term, 'evolutionary misfiring', where an evolved instinct leads us to do things for survival in the wild that no longer necessarily help us survive in a modern human society. Take, for example, sex - a survival trait which is rarely used for survival anymore, but has become a world-wide obsession in spite of this. There are plenty other examples, including foreign aid and the death penalty, so it isn't as though we're too smart to be unlikely to act on primal and often unnecessary instincts.

-Quip