Which type of a person intentionally starts using a known addictive, carcinogenic substance like tobacco?

Well, at one time: About half the population of the us did, which includes an awful lot of "types" of people. People start smoking generally when they are in their early teens, when they believe they are immortal and invincible, and nothing can hurt them. They also do it to irritate their parents and be closer to "cool" peers. By the time they are addicted to nicotine, withdrawal makes it hard to stop.