"There is a theory which states that if ever anyone discovers what the universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another which states that this has already happened."

-- Douglas Adams, The Restaurant at the End of the Universe


And, of course, anything Feynman ever penned is pure gold. I don't even know where to start with those ones. Maybe "I'd hate to die twice. It's so boring."