When I was a teenager in the 1990s, I wrote a journal entry that began: “Dear older me.” I won’t go on, because of course it’s too embarrassing for words, but the gist of it was this: I was anticipating that my older self would at some point feel nostalgic about my teenage years, and I wanted to set the record straight by describing what was boring and unsatisfactory about them.

What I didn’t anticipate was that it wouldn’t be “older me” who would feel nostalgic about the 1990s, but a younger generation which wasn’t even around back then. AI-generated videos set in the 1990s and 1980s have been popping up on social media this year in which teenagers hang out in video shops, ride the streets on their bikes, and talk about how good life is compared with 2025. In one, a girl and boy watch the sunset on a suburban street. “I heard in the future, no one even goes outside any more, everyone just stares at screens all day,” the girl says. “Man, that’s messed up,” the boy replies.

What’s going on? Agnes Arnold-Forster, author of the book Nostalgia: A History of a Dangerous Emotion, told me that “nostalgia for a period you haven’t lived through — whether you’re young or old — is pretty common and has been around for a long time.” What is different now is that social media allows young people to “publish their thoughts and feelings in a way that wasn’t so easy in the analogue era”.