Bad habits are habits you want to get rid of – they are the opposite of regular habits.
Bad habits do not show in the habit widget and cannot be scheduled onto the calendar. They also do not count into the number of incomplete habits on the habit tracker menu item (see our article on badges and notifications for more information), and current/record streaks are not calculated for them.
It might be more convenient to flip the habit and track it as a positive one, for example, "Avoided smoking today". Though a bad habit is useful if you want to track how many cigarettes you smoked – you would use a many-times bad habit for that.