Inside accounts of Presidential advisory groups make it clear that the failure to express dissent can have direct, immediate, and severe consequences...Because so much disagreement remains hidden, our beliefs are not properly shaped by healthy scrutiny and debate. The absence of such argument also leads us to exaggerate the extent to which other people believe the way we do. Bolstered by such a false sense of social support, our beliefs strike us as more resistant to subsequent logical and empirical challenge.

- Thomas Gilovich