"Brains are survival engines, not truth detectors. If self-deception promotes fitness, the brain lies. Stops noticing— irrelevant things. Truth never matters. Only fitness. By now you don't experience the world as it exists at all. You experience a simulation built from assumptions. Shortcuts. Lies."
-Blindsight, Peter Watts
That and other videos that will keep you up at night wondering how your evil brain will screw you over next: http://viscog.beckman.uiuc.edu/djs_lab/demos.html
Except the dinosaurs, all was snagged from the Blindsight book, linked above. Seriously, go read it. Amazing, brain-warping stuff. Very Matrix-what-just-happened-to-the-world-I-thought-I-was-living-in'y