20, maybe even 15 years ago it was considered rude to talk on a cellphone in public. Conversations with someone physically present were considered a different category of thing to phone conversations, and taking up public soundspace with a phone conversation was breaking a social rule. As far as I can tell that has pretty much died off in most contexts, at least in (my part of) the US, and I’m quite glad. (The year in which the only reasonable way for me to chat with my partner was by taking long walks through the city and sometimes parking myself in a Dunkin Donuts would have gone pretty differently for one thing.)

But I wonder about “watching TikToks in public” discourse. I don’t think it’ll go the same way - earbuds are so readily available to most people - but I’m prepared to be surprised.