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.
A few ideas:
the difference between Nobly Confessing One's Limitations and actually preparing to be wrong. I was pretty guilty of the former in the past. I think I'm probably still pretty guilty of it, but I am on active watch for it.
the idea that one should update on every piece of evidence, however slightly. This is something that I "knew" without really understanding its implications. In particular, I used to habitually leave debates more sure of my position than when I went in---yet this can't possibly be right, unless my opposition were so inept as to argue against their own position. So there's one bad habit I've thrown out. I've gone from being "open-minded" enough to debate my position, to being actually capable of changing my position.
That I should go with the majority opinion unless I have some actual reason to think I can do better. To be fair, on the matters where I actually had a vested interest, I followed this advice before receiving it; so perhaps this shouldn't be under 'useful' per se, although I've improved my predictions drastically by just parroting InTrade. (I don't bet on InTrade because I've never believed I could do better.)
Sticking your neck out and making a prediction, so that you have the opportunity to say "OOPS" as soon as possible.
This isn't quite right - for example, the more I search and find only bad arguments against cryonics, the more evidence I have that the good arguments just aren't out there.