I'd have up voted you if you hadn't said "period". Unhealthy behavior is a biggie but anyone that says "here, this ONLY is the problem" just adds to the mess.

The US health care system is melange of many complex and perverse incentives. I recall a study saying unhealthy behavior adds at most 50% to costs but costs have increased many more times than that in the last thirty years. The billing system, medical education system, end-of-life-care, the health insurance system, ad-nauseum. It takes a LOT of crazy schemes to eat up 20% of the GDP of the once-most-prosperous country in the world.