Me, I never abused it. That's why I never got addicted to it. To me, weed was something special I used to listen to music. Special things stop being special once you do them every day, so I never did.
I do not really think that there are such reasons to somehow 'abuse' of marijuana use, it just happens uncounsciously when people first start doing it for fun, then it gets to a point where they ca n not really leave it and it finally becomes an addiction or something that people actually abuse of, however there might be a milion reasons to get addicted to it.
I also think that peer pressure or wanting to belong in a group is one of the most common reason why someone would try using it. I think it is more true on places where marijuana is considered legal as they can persuade someone to try it without thinking anything bad about it or thinking they will not break any law.