Recently we ran a video which debunked the myth that we only use 10% of our brain's capacity. There's another myth circulating out there that has also been debunked for quite some time but which nevertheless persists as something of an urban legend. It's the notion that people can be meaningfully classified as either "right-brained" or "left-brained."
Here's a video featuring a rather frenetic speaker explaining that it just ain't so:
The speaker makes a good point that the terms "right" and "left-brained" do have rhetorical value as aptitude descriptors, as long as we don't take them literally.