Discipline is the suppression of base desires, and is usually understood to be synonymous with
restraint and self-control. Self-discipline is to some extent a substitute for
motivation. Discipline is when one uses reason to determine the best course of action regardless of one's desires, which may be the opposite of
fun.
Virtuous behavior can be described as when one's values are aligned with one's aims: to do what one knows is best and to do it gladly. Continent behavior, on the other hand, is when one does what one knows is best, but must do it by opposing one's motivations. Moving from continent to virtuous behavior requires training and some self-discipline.