In a video found here, the famous magic team of Penn and Teller illustrate how people’s expectations can change their perceptions. Customers at a fancy Los Angeles restaurant were presented with a water menu purporting to list waters from various parts of the world and sold from bottles with elegant labels at high prices. In fact, all the water came from a garden hose on the restaurant’s patio, but customers nevertheless discussed all the subtle differences they perceived–based solely on their expectations.