Dilbert: And that is my idea for our new product. Are there any ignorant objections? Man: Your idea is totally ridiculous! It's like you're tying to build castles in the sky! Dilbert: Have you heard of Air Force One, the plane used by the president of The United States? That's basically a castle in the sky, and someone built it. Man: Well, if your idea is so good, why hasn't someone already done it? Dilbert: I'm guessing that everyone else had co-workers like you.