Actually, our nutty professor and related doom peddlers really need to step up to the podium and tell the whole class exactly what went wrong with their predictions and why. That they're conspicuous by their silence tells you everything you need to know about their convictions, if not their character.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'