There was a guy on reddit who posted his story of trying I think it might have been herione once, figuring what the hell, once is fine and holy hell is it scary to read what happened and how quicky he became addicted because he was forever chasing that first high. Pretty sure he completely fucked his life up because of "once is fine". It's insane. I figure that's also what happens with meth. People figure why not and end up completely fucked.