Men become builders by building and lyre-players by playing the lyre; so too we become just by doing just acts, temperate by doing temperate acts

Aristotle had a unique perspective on virtue, stressing the importance of habituation. We act virtuously not because of some inner essence of virtue but, partly at least, by developing good habits. Behavior itself determines results. He drew an analogy with artistic pursuits, like lyre-playing.

Of course, both good and bad players of the lyre become lyre-players by playing the lyre, as he goes on to point out. The habit might not be sufficient, but it is necessary. Writers write rather than sitting around talking about what they are going to write in the future.

Many negative behaviors also fall in the category of the "habit." The word itself is a metonymy for an addiction to drugs, in popular parlance. Most negative behaviors are not one-time phenomena, but persistent patterns of behavior.