We humans have the strange ability to get addicted to everything under the sun. Whether it's sex, food, writing, masturbation, chewing gum, cutting, anger, reading, tanning, plastic surgery, or licking cats, there is an addiction for everyone. Just because a small group of people find themselves addicted to something, does't make the substance or act itself addictive. While there are things out there that are addictive and can be judged so by their high addiction rate, (crack, heroin, meth, nicotine, alcohol) I really do not believe that marijuana falls under this category.
I myself smoked weed off and and from 21-33. There were quite a few times where I did quit in that period and I never had any problems staying away from it. To tell you the truth, I can't remember the last time I've smoked it since then, but it's been a few years. I've had plenty of friends who were the same way. Toked until they choked for years and just quit for good, either for the sake of a job or because they just felt they needed to move on with their lives and having an illegal substance just wasn't worth it.