An article - The Abilene Paradox: Is the Managment of Agreement Still an Issue - linked from a David Pogue blog post.
It is provocative to ask why people would actually speak against their own desires. What psychological reasons are there for doing something that is bound to result in both individual discomfort and in a lack of full and valid information for the group and our organizations? It is believed, according to Harvey, that people behave in this manner because they are afraid of the unknown. His hypothesis, quite different from others, is that we know what we are afraid of and that it generally has to do with loneliness, being left out, separation, and alienation. To avoid these, we will actually act against our best interests, hoping to be "part" of something, members of the whole.
We also tend to believe that any decision or action is better than no action at all. The problem is that there is incomplete information in individual minds. The need to act together, to be seen as cohesive, overrides the need to be explicit about group assumptions, desires, opinions, and even facts. Harvey calls this "action anxiety" and he believes it works in close conjunction with another piece of the paradox puzzle: negative fantasies. These are fantasies each individual harbors of what they think would happen if they actually spoke their minds and offered their desires or opinions to the group.