I am frequently telling people to stop smoking, not in an annoying way, certainly tactful, not like your-annoying-friend-you're-thinking-about-now-would-do-it. They always agree with me and usually appreciate my support.
If I tell somebody to put down the donut so to speak, lose weight, often they will get offended. Obesity is as dangerous as smoking. Why is our society anti-smoking but pro-fat? Honestly I've had enough of this shit.