> No reason to be wary of recreational use. No more so than you might of caffeine

You should be wary of caffeine use, especially if your culture does not have any rules about its use, or complete enough understanding about its effects. We like drugs because they work, but the problem is we do not know what they do over larger timescales or how to fit them into your life. Weed is a relative newbie in the average American's life and we would be silly to not respect the drug enough to be wary.