Super smart people are so good at constructing plausible narratives that they can convince themselves of almost anything. You have to actively look for ways to disprove your own narratives. This is hard because they sound so plausible.
But where does critical thinking come in? Seens there should be a heuristic or generalized approach for deciding what to believe. Epistemology, I suppose.
And this should all preface the formation of our ideas in the first place.
Socratic Method is one way, I can recommend "The Socratic Method - A Practitioners Handbook" by Ward Farnsworth.
(any recommendations on that specific book?)
When people trust themselves above all it means we'll never have a utopia because we all can't help but believing some pretty stupid stuff at times. But at the same time we'll never have an absolute dystopia, because the diversity of thought ensures we'll never all fall off the deep end, or be pushed off it, together.
On a daily and regular basis, I trust myself, my thought process, experience, rationale, etc. I spent decades consciously honing my analytical and logical skills and I will spend lifetime continuing to do so. And it serves me well.
But, I believe, there needs to be a "safety valve". A "who watches the watchmen", somebody to provide a sanity check on your own rationale and story and narrative and thought process, which left alone can take you from first principle to lala-land, one seemingly logical step at the time, over years if needed. There needs to be an external influence/person who can, if situation calls for it, help you see things from an external yet trustworthy perspective, when your internal narrative, the "personal story of your life", starts strongly diverging from objective consensus reality.
(on a deeply personal note, I'll freely admit my sister did that for me ~15 years ago - after for a year or so I spun an increasingly personal internal narrative about something in my life, with a short but incisive comment, she momentarily enabled me to see myself through her eyes, and not love what I saw, and get that instant split-vision of my narrative and external narrative of what and why and how and whence I am where and how I am. Anybody else, I would've discarded or been defensive or otherwise ignored it. And I see many people around who desperately need a "grounding" or "reality check" or "slapping sense into" or "righting the boat" or whatever we choose to call it, but don't have anybody that can reach them. )
And I'd take this a step further -- the ability to unlearn/reprogram is a mark of intelligence, but ego definitely factors in as well.
I trust myself very little when it comes to many topics, because I have next to zero expertise in them, and I know that "common sense" often does not lead us to good decisions on topics where we have little understanding. That doesn't mean I'm going to outsource decision-making to others who are experts on those topics, but I am probably going to most often do what they say, after applying their information to my own situation and determining what seems reasonable and doable.
As an example, I will most likely get the Omicron-tuned COVID vaccine when it becomes available, assuming the relevant experts I trust say that it's a good idea. I have no idea if I really need it, but the non-zero threat of long COVID, coupled with the fact that we still know fairly little about the long-term effects of having contracted COVID, means I would rather face the very low risk of vaccine complications than increase my risk of getting COVID, with the attendant risk of it being something that causes lingering health problems for some significant part of my life. I won't be outsourcing my decision-making to a third party, but I recognize that I do not trust my expertise in this field (since I do not have any), and will allow those with expertise to heavily inform my decision.
One thing that seems to be common and is my working hypothesis, is that they're so smart and so respected in their field (or, in subset of cases, arrogant), that they simply trust themselves more than anybody else. There is nobody in their family and friends who can truly "slap some sense into them"; provide perspective, course-correct, nudge into objective reality or mainstream story, whatever we call it. I've actually asked a couple of them point blank - and they admitted, nope, there's nobody that they trust more than themselves. Couple of them even said - if you don't have trust and faith in yourself, you're weak.
So I'm hoping I'm somewhat inoculated against going off the deep end by having at least 3 people in my life (wife, sister, and one good friend) who can, and have, slapped some sense into me when I was going off the rails.