After thinking a lot about it, what I miss the most is the pre-Internet days. Or I should say the pre-"massive Internet adoption" days, I'm fine when it was non-essential for life. What I really miss is how slow some things used to be... when a movie, game or album came out, there was enough time to absorb it, enjoy it to the fullest (or be thoroughly disappointed by it). Nowadays these things are no longer an "event", it's just about the hype about what's coming next, and as soon as it's there you pretty much have to move on to the next big thing at breakneck speed.
With a game, for example, the hidden secrets and that sort of stuff took time to be unraveled, sometimes you would find it on a magazine or a friend who stumbled into it. All that is gone now, when a game comes out it gets fully datamined in less than 24hs and in the same period of time you already have thousands of 100% playthroughs. And the key here is that unless you cut yourself off the Internet for a while, you can't avoid it.
It also has affected my work as a software developer. New versions of libraries and frameworks are released almost daily, many times breaking compatibility with the previous versions and threatening to end support unless you update. All of this without providing any real added value. It's 2022 and we're still finding new and innovative ways to render an accordion in HTML, while using extremely complex algorithms behind the scenes to determine which annoying adds we're going to show to the hapless users. Or crypto mining, another example of heaps of processing power absurdly wasted on inane things.
I would pay good money to get back to those saturday mornings when my friends and I would go to the (not entirely legal) games store with a box of floppies to get the "latest" stuff, fooling around waiting for the game to install. Even if it was a disappointment, we would go back to Wolf3D/Doom (or downloading 640x480 pics of Pam Anderson at 2KB/s) and have a lot of fun.