It's like talking to a brick wall because either they like smoking, or they think they have no chance of quiting. Nicotine is the most addictive drug (Call it what you want it, it's a drug) in the world, followed by heroin. In my opinion, Heroin and Cigarettes are equal in how bad they are for your health, it's just heroin kills/effects you quicker.
The kill thousands every year. But what can you do? Its hard for them to stop