The brain is constantly producing stupid thoughts. Usually we try the best we can to not reveal them, but a lot of them shines through anyway. Sometimes, though, the head comes up with clever stuff. We then think to ourselves, “Oh boy, this is clever. I have to jot it down so I don’t forget about it.” The clever stuff eventually ends up in notebooks, blog entries or, if the person is able to write well, it might end up in a book. That is the reason you can find so many clever books. All the stupidities are filtered away. The reality of things is heavily censored in clever books.