There's an article in the Aug. 23 New Yorker by Joshua Rothman about rationality. My reaction to it feels offbeat but not irrational.
I'm certainly capable of reacting emotionally, mostly in spontaneous situations, but I think I run my life decisions, on a scale running from "plan my next vacation" on up, on a fairly rational basis as average people go. I modify my practice over time as I learn more about what works and what does not. That's about becoming more knowledgeable, not more rational.
Yet I have no desire to join a rationality movement as described in this article. It does not seem to me a rational thing to do. I read Scott Alexander, who's a figure in that movement, but I read him because he's entertaining and often informative, and unlike some of his fellows he does not hold up rationality as a goal in itself.
What I find missing from comparisons of rational and supposedly irrational behavior is a lack of consideration of the difference between people's individual goals and personalities.
Rothman describes his college friend Greg, a conscious rationalist, as particularly interested in making rational study of monetary investments. Such an interest is sort of a default example of rationality in action, and for someone like Greg, who became a hedge fund manager, focusing on it makes sense.
But I would say, "I'm not particularly interested in studying investments. That's not what I want to spend my free time and my intellectual energy on; there are other things I prefer to do. Consequently, even if I did work at this, I'd probably not be particularly good at it.* So since there are people who make their living advising other people at investments, I can have them put me in mutual funds. Then there will be two levels of expertise watching over my money. They could make mistakes, to be sure, but then so could I if I were doing this. And I think I can avoid the small risk of con men by not using people offering implausibly high returns out of black boxes." That strikes me as a rational reaction from someone with those priorities.
Rothman defines Charlotte Lucas as rational when she accepts Mr. Collins' offer of marriage, implying that Lizzie was irrational to refuse it. But they're different people with different needs and expectations. Charlotte says she's not romantic. She is only concerned with financial security, and as a married woman demonstrates her priorities, eking out a life as detached from her irritating husband as possible.
That's fine for her, but Lizzie wants partnership and a meeting of minds out of marriage, and it would have been irrational for her to make the decision which was rational for Charlotte. Lizzie's only mistake here was to be surprised and not realize how different Charlotte is from herself. That's a lack of knowledge, not of rationality.
*This isn't always the case. I spent my school years perplexed at the fact that I was both very good at math, and found it exceedingly boring.