I think it is a two fold issue: one part is related to behaviors and the other is related to healing. We can logically determine that drinking needs to stop, but our brains are sending out impulses to use again. Focusing on behaviors distracts us from the impulses, allows time to let the brain heal and restores most normal cognitive functioning. However, the old reward associations are still present (i.e. alcohol = good) and can be fired back up by drinking again.
Normal brains will send signals to avoid actions that harm a person, which is why normal drinkers will stop. Their brains have not become altered through addiction. However, if they want to adapt a new habit, then they still need to focus on actions.