I think the average person just stumbles along without ever thinking about it much. Seems odd.
A book that I HIGHLY recommend is
Sapiens.
One of the most important things about people, moreso than the ability to reason, is the ability to create and sustain myths.
A good example (and one used in the book) is money. What is money? Green pieces of cloth/paper with numbers printed on them? Worthless for nothing other than wiping your ass or burning for heat if we didn't all believe that it was special and worth something. And this is the basis for all commerce in America?
Other myths are religions, borders, nations, etc. These ideas only have power because we all kinda just agreed on them. What is an "American"? What is an "America", for that matter? The human brain can't really comprehend more than about 150 people, but we've all agreed that 340M people are all "like us" to the point where we pay taxes, go to war, vote, make decisions, all as a group.
When you take a myth like "money" and subject it to strict scrutiny, you realize that it
ONLY has meaning because we all agree it has meaning. And the even sillier thing about it is that people argue over it. Goldbugs will argue that fiat currency isn't "real" money, but gold is. Ever tried to go to Walmart and spend gold? Governments will argue that bitcoin isn't "real money" but there are places I can go spend it. Government fiat currency is "great" money, until you're Weimar Germany or Zimbabwe 20(ish?) years ago or Venezuela over the last 5-10 years.
Religion (abstracting organized religion as an institution AWAY from the idea of whether or not there's a supreme being) is a very powerful myth. It has done tremendous good in the world, bringing people together, helping people in need, helping people cope with the absurdity of living, helping people feel like they're part of something--a community, a purpose--bigger than themselves. It has also done tremendous evil in the world, and been a major force over the centuries in war, bigotry, and division between people. (Government/nations have done the same, and people over silly divisions like race/etc have also done the same; I'm not singling out religion for this.)
So, yeah, most people go through life never thinking about any of these myths. If they did, and too many started questioning them, they'd fall like a house of cards, because it's really hard to actually comprehend that they're myths and then at the same time support and sustain them "because they work".
Society depends on myths, and myths depend on not being too closely scrutinized lest we realize they're just myths.