Experts predictions are really only very slightly better than throwing darts at a dart board. So why is it they are so confident? It may be that, first of all, many experts are making quotunquote predictions in hind sight. The other reason i think confidence ends up becoming a hall mark of commentators who weassume to be experts at what they do. And there might be a weak positive correlation between the confidence in your judgment and its accuracy.
Also: how do you recover from a bad day?