It works the other way as well -- mindless optimism in the face of the facts.
"All right, we're ready to launch the new offering and so are our clients."
"Excuse me, boss, but didn't the system's vendor say it couldn't work?"
"And the vendor's engineers, and our engineers as well?"
"Yeah, I guess."
"Why are we going ahead in spite of the fact that it can't work?"
(All I heard at this point was the wind whistling through his head. It became a familiar sound.)