smoking is very bad habit

Why the .... are you talking about something where you don't have any experience with?? you don't need to mention that smoking is a bad habit, ofcourse it is! But it's also for decades known.. you want everybody not to smoke, if I understand you're English, well it's easy for you to say as a NON smoker, I guess you never smoked as well? Ok, maybe tried it but never had it as a habit! Because then you would know how hard it is..

everyone knows. but a habit is a habit. they will feel uncomfortable if they stop smoking.