Been a smoker since I left my father's home, honestly think I was addicted to nicotine before I even lit up considering there was this constant visible thick smoke haze in my childhood home all the time, so I was breathing the stuff second hand before ever touching a cig myself. Ended up moody and aggressive at the drop of a hat shortly after leaving the home, then I started smoking and that moodiness went away, so honestly I think I was addicted long before I picked it up even though I knew as a child what effects smoking had on the body and even tried to get my parents to stop smoking, now I know why trying to stop was so hard for them.
But in truth I'd rather be a smoker than a drinker, at least cigs won't put me into a violent stupor, then again I also hold a major grudge against hard liquor, and for good reason.