Followup to: The Most Important Thing You Learned
What's the most frequently useful thing you've learned on OB - not the most memorable or most valuable, but the thing you use most often? What influences your behavior, factors in more than one decision? Please give a concrete example if you can. This isn't limited to archetypally "mundane" activities: if your daily life involves difficult research or arguing with philosophers, go ahead and describe that too.
Shut up and do the impossible, or lesser levels of 'dont run away from the problem'
In particular, the AI box experiment applied to persuasion in general. I make a lot more progress in argument when I focus on changing the persons mind, rather than picking apart their flawed arguments or defending mine