Sorry, should have added a link, but I have heard it/read it multiple times:

"""In his younger years, Gates' gimlet-eyed idealism manifested itself in stubbornness and self-righteousness, an unusual boldness, and a tendency not to suffer fools. Most people who have worked closely with him can recall more than one instance in which he reacted to a comment or idea by standing up and hissing, "That's the stupidest thing I've ever heard in my life.""""

http://money.cnn.com/2008/06/20/technology/gates_after_microsoft.fortune/index.htm