Learn to criticize ideas, especially your own. Most new ideas are wrong or inadequate. If you don’t reject most of your ideas promptly, then you’re almost surely fooling yourself, and if you also spread them, you’re almost surely polluting the intellectual world. But if an idea really seems to stand up under testing, try filling in more details, and criticizing it again.
— K. Eric Drexler, Engines of Creation 2.0: Advice To Aspiring Nanotechnologists