“Thinking with a sleep-deprived brain is like hacking your way through a dense jungle with a machete. It's overgrown, slow-going, exhausting. The paths overlap, and light can’t get through. Thinking on a well-rested brain is like wandering happily through Central Park; the paths are clear and connect…”
— http://www.fastcompany.com/3059634/your-most-productive-self/your-brain-has-a-delete-button-heres-how-to-use-it, fastcompany.com