"Stock up on Cheetos and Mt. Dew BEFORE you spark," a local police department in Kansas recently tweeted, warning "potheads" not to drive on 4/20.  While stoners may roll their eyes at the stereotyping, science, it seems, is on the police department's side. Weed impairs our ability to think, organize, and pay attention, studies have shown. And it's not usually associated with productivity and motivation.  Yet, some users feel more focused, even productive, after consuming or smoking weed — even though there's no scientific evidence cannabis acts upon the motivational circuits in our brains

Read more at Mashable.