Inventor Thomas Edison had a simple test he used to measure the "unexpectedness quotient" of prospective employees. He would invite a candidate to lunch and serve a bowl of soup. He would then watch to see whether to person salted his soup before tasting it. If he did, he wouldn't be offered the job. Edison felt that people are more open to different possibilities if they don't salt their experience before tasting it.
-Roger Von Oech, as excerpted from Expect The Unexpected (Or You Won't Find It): A Creativity Tool Based On The Ancient Wisdom of Heraclitus