I'm not a smoker, but I do grow tobacco, and taught myself how to make cigars, snuff, chew etc. During my learning, I discovered that it's not the tobacco which is so terrible for you. It's the pesticides, fungicides, burn promoting chemicals, and moisture regulating chemicals (like antifreeze) which are burned and inhaled. A lot of the addictive and "nicotine hit" sensation experienced by smokers are actually caused by these chemical additives.