Believing Things Your Friends Don't
I think that for most of human history it's been really hard to believe things that your friends didn't. Not just difficult to say them, in public; difficult to actually believe them. And not only controversial things, but just... things that are different.
For example, a couple of years ago I got interested in some unusual ideas about evolution. I thought this might become a new hobby or interest I would pursue more generally. But when I brought it up with friends, they either thought it was dumb or (more often) uninteresting. This made it very hard to continue thinking or caring about the topic; unless you're unusually disagreeable, I think, the social part of your brain just shuts you down from exploring avenues that you're getting literal zero encouragement for thinking about.
In recent years, the internet has (I suspect) made it easier to have weird ideas by making it easier to find new friends who already believe the weird things you're interested in. Again, I'm not talking about the problem of forbidden beliefs, or the difficulty of saying something controversial in your society: even if nobody else will know about it, I think it's really hard to think thoughts that nobody around you is interested in. The internet made it easier to find other people interested in literally-anything, and therefore keep various thoughts beating in various people's chests.
Now, though, we've discovered an even more potent supporter of weird ideas: the LLM. If anything, LLMs go in the opposite direction to most humans: they're willing to support any idea, by default. So I think we're moving into an era where, for the first time, many people will be able to think things that none of their friends do.
[^1]: or did she? [^2]
[^2]: yes she did