Good rule to follow:
One of the most important skills I see in successful (and good) people is to constantly reevaluate assumptions. They make predictions based on various inputs, some of them unknown, and reevaluate based on what they got right and wrong. They trust people not because they're always right--no one is--but because if you're constantly seeking the truth it's easy to identify those who are doing the same.
If you were confident that Donald J. Trump was going to lose, maybe you should question what else you "know" about him. Maybe the people who misled you about his electoral chances have misled you about other things.
In the words of Cormac McCarthy, "If the rule you followed brought you to this, of what use was the rule?"
