I dunno, weed's fun, but it's not really addictive.
Anything you enjoy doing can become addictive... gambling, sex, exercise, even smoking the whacky baccy.
Addiction is, with non physical dependency, a psychological disorder... to which I am a heavy sufferer. I smoke constantly, have done for 8 years. All day, every day. I had a 3 month break once, and you know how they say that if you lay off it for a while you get mega-stoned when you next smoke? Bullshit. I smoked, and smoked and smoked, it was like I'd never been away and the previous 3 months had never happened.
I still get stoned, but it's like I can ignore it if I want to... in other words, it doesn't get in the way of me doing the things I need to do. Whenever I have friends around they visit the bathroom a lot, its not because they have weak bladders, it's because they need to go wash their face to try and pull themselves together. The only thing that stops me smoking is my natural 6-8 hours sleep a night.
Although soon (after this weekend), i'm going to be having a break from the smoking... around a month.