So the second factor is that most people are rational enough for their own purposes. Oh, they go on wild flights of fancy when discussing politics or religion or philosophy, but when it comes to business they suddenly become cold and calculating. This relates to Robin Hanson on Near and Far modes of thinking. Near Mode thinking is actually pretty good at a lot of things, and Near Mode thinking is the thinking whose accuracy gives us practical benefits.

Seems to me that most of us make predictably dumb decisions in quite a variety of contexts, and that by becoming extra bonus sane (more sane/rational than your average “intelligent science-literate person without formal rationalist training”), we really should be able to do better.

Some examples of the “predictably dumb decisions” that an art of rationality should let us improve on:

• Dale Carnegie says (correctly, AFAIK) that most of us try to persuade others by explaining the benefits from our point of view (“I want you to play basketball with me because I don’t have enough people to play basketball with”), even though it works better to explain the benefits from their points of view. Matches my experiences, and matches also many/most of the local craigslist ads. The gains if we notice and change this one would be significant.
• Lots of people decide to take a job “to make more money”, but don’t bother to actually research the odds of getting that job, and the average payoff from that job (the latter, at least, is easy to look up on the internet) before spending literally years training for the job. Even in cases like med school. Again, significant payoff here, and in this case fairly minimal willpower requirements.
• Lots of us tend to mostly stick to our own opinions in conversations, even in cases where our impressions are no better data than our interlocutor’s impressions, and where the correct opinion can actually impact the goodness of our lives (e.g., which course to take on a work project whose outcome matters; which driving route is faster; which carwash to try) (these latter decisions are small, but small decisions add up).
• Similarly, lots of us decide we’re “good at X and bad at Y”, or that we’re “the sort of people who do A in such-and-such a specific manner”, and quit learning in a particular domain, quit updating our skill-sets, keep suboptimal beliefs or practices glued to our identities instead of looking around to see how others do things and what methods might achieve greater success. Lots of us spend far more of our thinking time noting all the reasons why we’re best off doing what we’re doing than we do looking for new ways to do things, even when such looking has tended to give us useful improvements.
• Lots of people run more risk of death by car than they would upon consideration choose, e.g. by driving too close to the car in front of them (the half-second earlier that you get home isn’t worth it) or by driving while tired. At the same time, lots of people refrain from enjoyable activities such as walking around at night or swimming off the coast of Florida despite the occasional sharks, in cases where the activities in fact pose nearly negligible danger, but the dangers in question are vivid and easy to over-estimate.