Why do people who hate that they overeat keep overeating? Why do people who know that their girlfriends or boyfriends are bad for them keep taking these girlfriends and boyfriends back? Why do so many people who want to go to the gym never actually bother to do it? These circumstances can be explained, at least partially, in terms of desires changing and conflicting with each other. What we want when we consciously reflect on a situation sometimes differs from what we want when we are actuall...