I have always thought that the "we use only 10% of our brain" factoid was BS.

Our conscious mind is like a filter. It reduces stimuli so that we can perform our utilitarian tasks. But that does not mean that the rest of the brain is not in use. Dreams are one of the ways that the 90% puts information over into the 10%.

When the filter is removed, you are trippin' balls! You would spend all your time grooving on a pebble of sand or a blade of grass. What good are you then to do your slavemasters?