I have a close friend who fucked up his first year of college royally by becoming a habitual pot user. After the realization that he was actually going to get k

I have a close friend who fucked up his first year of college royally by becoming a habitual pot user. After the realization that he was actually going to get kicked out of school for academic probation, he quit cold turkey. Multiple tokes daily to zero, overnight. He turned his grades around and graduated with distinction. After he graduated, three years later, he started smoking again. He says he only smokes once or twice a month and even then only on weekends. I honestly believe him when he says he just enjoys it and feels no real addiction. It seems no different than how I am with alcohol: mmmm beer. That's just one anecdote. I don't know if that is common at all.