All brains are good brains. However, information can affect the brain in ways that can distort its functioning. When negative information has taken over the natural workings of the brain, you could say that a good brain has become a bad brain. The brain naturally distinguishes positive information from negative, but sometimes we simply lose trust in our brain, allowing outside information to run the show.
Ilchi Lee, Brain Wave Vibration: Getting Back Into the Rhythm of a Happy, Healthy Life
brain, brain-wave, meditation, natural-health, non-fiction