Millions of young people are now growing up surrounded by the fact of legal marijuana. Maybe it’s medical dispensaries in their state. Maybe they routinely smell pot smoke drifting through their backyards. Maybe their parents have used the drug for as long as they can remember. Though it’s not a topic of much discussion, it’s very likely that these young people will develop an attitude of complete tolerance for this drug. The dangerous effect of that attitude should not be underestimated.