Most of the problems I have with weed I have with just about everything else. Enjoying it responsibly, yes, there's no problem, but Marijuana is just like every substance with the wondrous negative of making your home, and the area around it smell like shit. To say that it can't be considered self destructive is a joke. Alcohol can also be self destructive. Just like video games, Oxycontin, cigarettes, gambling... and so on. Although, all of these have their own positives if enjoyed responsibly!
Of all the people I know smoke the stuff, only 4 do so responsibly. The rest all blow their pay cheques on the hourly weed bill, talk like retards, and smell like shit as a result. They say it's harmless, and it brings you together, because everyone wants to share their blunt, but it's not just the weed they're sharing, it's the hopes of addiction as well.
Again, there are people out there who do it responsibly. Who aren't smoking one in the morning, and keep it to a smoke maybe once every odd week. I've got nothing against them, and they don't seem to have the affinity of that goddamn smell. It's good in my opinion that it's legalized, but there should be a lot done to educate people on it's affects, and that's not going to happen unless the public school system gets a massive overhaul. This legalization is too early.