Belief in Impossible Things
There is probably no job on earth for which an ability to believe six impossible things before breakfast is more of a requirement than software project management. We are routinely expected to work ourselves into a state of believing in a deadline, a budget, or a performance factor that time subsequently may prove to be impossible.
— Tom DeMarco and Timothy Lister, 2003
From the book Waltzing with Bears: Managing Risk on Software Projects