By not quitting, you are missing out on the opportunity to switch to something that will create more progress toward your goals. Anytime you stay mir… - Annie Duke

As Nietzsche points out, regret can do nothing to change what has already happened. We just wallow in remorse about something over which we no longer have any control. But if regret happened before a decision instead of after, the experience of regret might get us to change a choice likely to result in a bad outcome.

If you put individuals together in the right way, such that some individuals can use their reasoning powers to disconfirm the claims of others, and all individuals feel some common bond or shared fate that allows them to interact civilly, you can create a group that ends up producing good reasoning as an emergent property of the social system. This is why it's so important to have intellectual and ideological diversity within any group or institution whose goal is to find truth.

When we have a negative opinion about the person delivering the message, we close our minds to what they are saying and miss a lot of learning opportunities because of it. Likewise, when we have a positive opinion of the messenger, we tend to accept the message without much vetting. Both are bad.