I'm not sure social media was ever sane. I distinctly remember thinking it wasn't back in my highschool days, so around 2007-2009, which was pretty much when Facebook completely took over the market in Sweden where I lived.

Before then I used to use lunarstorm. Was that the sane period of social media? Maybe, my memory is fuzzy: it's been a while.

At least with early Facebook one was mostly interacting with one's pretty close peers. Back when I joined, you still needed a .edu email address to signup, and there was no real discovery mechanism, so you mostly only friended people who you had met IRL.

Yeah it wasn't ever sane. It was just harder to onboard and you were still interacting mostly with people you knew. Now it's worse because you'll hardly ever interact with people you know.