What if things could turn out differently? How the multiverse got into our heads and didn't let go

Alternate universes are everywhere these days, from “The Flash” to “Spider-Man: Across the Spider-Verse.” There's a deep hunger for exploring other possibilities about how other worlds and other potential lives might unfold. And movies, books and TV shows about alternate realities and multiverses feed that appetite in an era when lots of people are asking exactly how we got to this point. They're also a lucrative storytelling approach for creators who want to make the most of their characters without ruining a “prime timeline." Some experts say that in the end, it's about experiencing stories in which someone looks for, and perhaps finds, a best possible self out of all the possibilities.