I'll confess, I'm a former smoker. I never really smoked that much, but dabbled as a smoker -- mostly during my late high school years and through college. I usually say I smoked "OP's", not a brand, but "Other People's" cigarettes. Because I often "bummed" from others, I sampled nearly every cigarette brand known to man.
My first cigarette was a Salem that was given to me by a friend's sister. I learned to inhale and remember getting dizzy. Then, I set a goal of learning how to blow smoke rings. Pretty quickly, I mastered smoke rings and once made about 30 rings from one drag of the cigarette. Thankfully, I never really got hooked and over time just quit smoking.
Because of my training as a safety and health professional, I know some about the ingredients in tobacco smoke. There are things like toluene (found in resins, solvents, and paint); phenol (a deadly chemical also used in resins); carbon monoxide (yep, the deadly gas that you have a detector for in your home). Health and safety laws would require either the elimination of or minuscule exposures to these substances if they were found in the workplace. Let's suffice it to say the stuff in cigarette smoke is not very good for you. Still, if you choose to do so, so be it -- it's your choice.
This brings me to the subject of an observable anomaly. Look for it next time you are out in your car. It's the person that is hanging their hand out of the car window with their cigarette because they don't want to get smoke in their car. It doesn't matter, hot, cold, snow, and even rain, their hand is out the window protecting the precious car interior. Then they take a big drag into their lungs and take extra effort to blow the smoke out the window to further protect the car.
What I can't figure out is why someone doesn't want smoke in their car, but will put it in their lungs. It does not make sense. Go figure.