I often promote Intentional Insights by talking about updating beliefs. I highlight the value of overcoming the negative emotions associated with learning about making a mistake, and instead encourage associating positive emotions with acknowledging reality and wanting to know the truth. This lets people take the best thing that they can from the mistake and move forward to achieve more!
Followup to: The Most Frequently Useful Thing
What's the number one thing that goes into a book on rationality, which would make you buy a copy of that book for a friend? We can, of course, talk about all the ways that the rationality of the Distant World At Large needs to be improved. But in this case - I think the more useful data might be the Near question, "With respect to the people I actually know, what do I want to see in that book, so that I can give the book to them to explain it?"
(And again, please think of your own answer-component before reading others' comments.)