Dan Ariely in his book talk  : 

We have an intuitive idea of stuff and we continue to work under the “spell” of our intuitions. But it is wise , despite our internal resistance, to check our intuitions from time to time. Collect data , Do a Survey , Simulate stuff , etc to empirically test your intuition and you will be amazed at the numerous ill conceived intuitions that we keep holding on to.

http://fora.tv/embedded_player