In todays world most of us live in organized societies. We share race, religion and cultural bonds. That being said irrespective of these similarities in our environment we all turn up to be different individuals. No two people responses are ever the same or identical. This is true even for twins! This is because ( I believe) in the way our brain adapts and assimilates all that happens around us. Our responses, reactions differ. This variety is what makes life interesting! The world would have been boring if all of us behaved in the same way like robots.