The guy who lives next door to me has emphysema and a sign on his door with a warning that oxygen is in use.  That though doesn't prevent him from going outside several times a day for a cigarette!  Have read that quitting smoking is a significant barrier in the treatment of emphysema.  I was a heavy smoker for a couple of decades and went through three or four attempts before quitting.  I never rant at anyone for smoking  But when you know that your life is at stake? 

Self-control in many areas is one of life's great challenges - and intense learning experiences.