The overwhelming human tendency (at least in cultures I know anything about -- I'm not sure whether it's universal) to a) force things into dichotomies, often terribly inappropriately, and b) try to map those dichotomies onto other, unrelated dichotomies (nearly always terribly inappropriately), has bugged the $%^# out of me for quite a while. Why are there so many of us who divide the world in twos over and over? Is it neurological; are humans (as a rule) even more binary-oriented than digital computers in out perceptions? (For computers binary is just an encoding, not a model.) Is it "merely" a meme infecting Western civilization from one of its ancient roots?
More seriously