Instead of continually talking about it, use your creative energy to solve the problem. A research was conducted at the University of Wisconsin to measure the affect of positive affirmation. A teacher, whose second graders continually got up from their chairs, was instructed to tell them three times a minute, to sit down. The children continued moving around. She affirmed their good behavior and praised the projects they were working on.
Smoking is bad.
Gaining weight is bad. Wrinkles are bad. The list is endless. When I am around people who smoke, I often hear remarks about how harmful it is for their health. If it bothers you that somebody smokes, certainly say so, but after that, drop it.