I smoked from age 16 to 23 and now I'm 27. I've had cravings for the stimulation that I miss for the last 4 years. I expect to have them for the rest of my life.
As a teenager, smoking was mysterious and therefore attractive to me because everyone seemed to agree that it's bad. The benefits were a secret that I had to discover through first-hand experience.
I don't regret quitting smoking and I'm not planning on starting up again, but the "smoking is bad" messaging is not as clear-cut as it seems.