You can fuck yourself up while smoking weed as much as you can do it while smoking regular cigarettes or drinking alcohol. Weed is nowhere harder than those two. (actually alcohol and cigarettes are worse than weed) I don't have any experience with cocaine but i know you can also fuck yourself up easily if you overdose it. All the others like meth, heroin, ex etc are complete shit. You should never ever do any of them.
I am not a weed addict, i smoke 2-3 times a year and i've seen weed addicts as i've seen social smokers like me. It all depends on your personality in the end. If someone is retarded enough, he can even destroy himself by getting addicted to tea.
LOL, like some people that got the jitters from drinking 5 cups of coffee a day.
I've never really tried weed but most info I find online says that it's not hard as say, cocaine. I don't know if it's possible to really get addicted to it. I mean, if it'll get you high while not developing dependency (and not ruining your brain as well) then it would be really good. Legalize it and try to make it available and hopefully people would be flocking to this legal high rather than chasing after the harder drugs.
You need to realize that it is the people, and not the drugs who are responsible for the crimes. Anyway, the number of crimes under the influence of drugs are much less than those under the influence of alcohol.
I guess the statistics would be different per country. Most of the crimes here in my country are committed by addicts while high on meth. Heck, I even knew someone who died while foolishly trying to steal while high. It seems to me that those high on meth have their decision-making impaired while retaining coordination. Someone really hammered on alcohol would have a hard time going around stealing stuff because they'll be too clumsy.