Parts of the deep brain retained throughout evolution for survival benefit take in all internal and external sensory input. This is processed, stored and responded to cognitively, physically and emotionally at 10 times the speed of conscious thought. Wackiness ensues. The worst of which is the tendancy to turn away like a blind man from people on the edge of the night. People in need or distress we run away from This has survival benefit, but does not make us nicer people or species. Conscious choices to not do this puts us under pressure.