I write a lot here about perception. The other day I thought of a fresh angle on that. I was thinking about how the internet, especially social media and its algorithms, allow you to create your own reality and then forget that you’ve done so.

I will see dozens of people talking about something—a new housing law, a deadly traffic crash—on my Twitter feed, and it creates the perception that everyone is talking about this. I remember, years ago, my feed was alight with this piece about YouTube’s bizarre kids’ videos, and my then-office had all read it. You really have to remind yourself that that means you and your handful of colleagues and a few people you chose to follow online read it, not everyone.

But I had a related thought, too, which I think is more interesting:...