Our minds deceive us. We can be looking right at something but not see it. We can remember details about an event but be completely mistaken. We can believe someone because they're confident, not because they're knowledgeable. Our minds deceive us. Take a look at The Invisible Gorilla: and Other Ways Our Intuitions Deceive Us by Christopher Chabris and Daniel Simons. Better yet, watch the video this book is based on. Then, if you're like me, you'll HAVE to read the book.