Why do people get sick and engage in unhealthy behaviors? is the public health system effective with this prevention?

People get sick because germs go from one person to another. People engage in unhealthy behavior because, for example, smoking. The cigarette company's specifically target people that think that they have a mental illness or if there stressed, they will lure in them with there advertisements. Also, if some kids parent(s) smoke, that will affect the kid in saying that they want to smoke. If you haven't seen the advertisements about people stopping others to smoke like truth or little lungs in a great big world, they help notify everyone of all age that whats in a cigarette or how bad it can give you cancer or bad lung disease. So yes the public health system is getting into people who do that to lower and/or stop smoking. I could list more examples if you want me to.

Ibelieve this would be an obstacle.