It’s just human nature—we resist rules imposed by others for our own good. If you try to impose those rules on yourself, from a moralizing, self-improvement point of view, you’re going to hear very quickly from the part of you that doesn’t want to be controlled. And so when you tell yourself that exercising, saving money, or giving up smoking is the right thing to do—not something that will help you meet your goals—you’re less likely to do it consistently.