Hypothesis: Habits are the highest-yield form of discipline.

We humans seem to have a sort of behavioral inertia, whether it's showing up at a job, maintaining an MMO addiction, or brushing our teeth. The ideal state is to develop positive habits (writing for an hour every morning, cooking a healthy meal every day after work, practicing the bass every Saturday afternoon), that reflect one's deepest desires. Deviating from existing habits, good or bad, is expensive in terms of willpower (brain glucose); but once a new habit is established, maintaining it becomes the default, and suddenly it requires very little energy.