My dislike of marijuana usage is based on the personal and the social effects. Personally, I appreciate it about as much as smoking, and for much the same reasons, although I find the sickly sweet smell even worse. I’m not looking forward to riding the subway with the person beside me reeking of marijuana - cigarette smoke is bad enough.
On the social side, I find increased marijuana usage about as attractive as increased alcohol usage for much the same reasons (although I find alcohol even worse). Certainly I don’t think that society benefits on the long run from people using artificial means to escape problems rather than solve them. And once again, it will be the lower socio-economic classes that will pay the biggest price for those individuals who become heavy users. The middle-class and higher can give kids who destroy their education a second chance, have family to give heavy users the opportunity to rebuild their life, have family to economically support those who make themselves unemployable, are more likely to have a job that will excuse the occasional inebriation, can hire care-givers and have good schools to support parental mishaps, etc.
Again, all of these apply even more so to alcohol, and I’m certainly not a fan of increased alcohol usage.
Anyway, I support efforts to discourage usage of cigarettes, alcohol and marijuana (especially public usage), but I do not support criminalization, which has costs way above any possible personal benefits.
And yes, I do support banning all sorts of things that bother me personally that other people might enjoy. Animal abuse for one.