Addressing 1) "Learning when you're wrong" (in a more general sense):

Absolutely a good thing to do, but the problem is that you're still losing time making the mistakes. We're rationalists; we can do better.

I can't remember what book I read it in, but I read about a practice used in projects called a "pre-mortem." In contrast to a post-mortem, in which the cause of death is found after the death, a pre-mortem assumes that the project/effort/whatever has already failed, and forces the people involved to think about why.

Taking it as a given that the project has failed forces people to be realistic about the possible causes of failures. I think.

In any case, this struck me as a really good idea.

Overwatch example: If you know the enemy team is running a Mcree, stay away from him to begin with. That flashbang is dangerous.

Real life example: Assume that you haven't met your goal of writing x pages or amassing y wealth or reaching z people with your message. Why didn't you?