Most smokers are recruited when they are 12 to 16. Smokers have a hard time quitting. For most it takes 3 to 8 honest attempts to stop before they are able to, and quite a few start smoking again after a few years of being a non-smoker.
I just quit. I know how this stuff works. For some 3 or 4 weeks now, I feel this constant urge to light it up again, even though I don't want to.
Smoking doesn't outright kill you off. It just speeds up the process a bit more. On average, you lose some 8 years or so, about the same amount you would if you slack off and never exercise.
The real crux is all the downsides you have before you die. You smell bad, you taste bad, you lose a significant amount of smell and taste, your general health drops, healing is slowed down, you waste a substantial amount of money, you are a slave to a habit, your fertility drops, you get more diseases and as you get older they get more severe, your lung capacity goes down, you have bad breath, you are extra pale and so on and so...
Smoking feels good. It really does. I liked it for the 15 years I did it. But despite how good it feels, it is not worth all the above effects. I'd rather chew gum.
Smoking adverts are not death adverts. Death is what they in ethical terms call "an unintended side effect". Smoking adverts advertise a lifestyle - a lifestyle that is quite overrated.
It's only after we've lost everything, that we are free to do anything.