Geez, where to start? Sorry about the novel. Anyway:
I miss video games being finished products without any stupid extra crap to sell afterwards that adds nothing to the game other than cosmetics(Thanks Bethesda).
I miss video games that didn't need day 1 patches or other types of heavy dev work on a just-released game.
I miss actual game expansion packs with substantial content instead of "battle passes" or whatever BS is currently floating around. Back in the day, there used to be a thing called an "Expansion Pack" for a game, and a good deal of the time the expansion pack was as rich as the base game itself. I know this isn't universally true, but it's very common.
I miss games that can't be simply broken permanently after sale on a whim due to centralized servers, especially games with single-player content.
I miss physical PC game orders with physical goodies. Back in the day you could go to a Gamestop and get free stuff if you pre-ordered and it didn't have to be the "Here's a car payment for a game with maybe 10 hours of content" edition. They were goofy little things, but some were seriously cool. I remember getting a lot of posters, keychains, stickers, and sometimes plushies. There were other things like figurines or music CDs but the one I really remember: a complete box set of the Unreal games series (Unreal to UT2004) when I pre-ordered UT3. I know games these days do provide older games in the series sometimes for free, but I think gaming lost something without those little "Thanks for pre-ordering" physical tchotchkes.
I miss cars & phones without GPS tracking that can be abused to make government surveillance of individuals trivial. Heck, any product that used to be useful that didn't use internet or gather user data. TVs, home theater receivers, game consoles, streaming devices, refrigerators, stoves, dish washers, clothes washing machines. Come on, man! I just want to keep my ice cream frozen, I don't need to be advertised to or monitored to do that.
I miss old stuff sold at auctions/yard sales/pawn shops being sold at a realistic price (video games, cast iron pans, stereo speakers, CRT TV/monitors, freakin' McDonald's happy meal toys). Like every stupid thing is being priced like some kind of investment and the trading/selling feels like playing the stock market. Yeah, we get it, you collect games. No, I'm not impressed you have a NIB copy of Chrono Trigger (which sold at $85 when it was released) and are now selling it at $250. Games are meant to be enjoyed, not gate-kept by "collectors" with more money than sense creating absurd niche markets. IMO if it weren't for emulation, a lot of the regular populace who didn't grow up with those games/consoles would miss out exploring them because of the arbitrary value placed on them. I've never even so much as seen a Sega CD in person, but emulation allowed me to discover great stuff like Popful Mail. FFS, they're
GAMES; they're meant to be played. You know what else was seen as a huge investment back in the day? China sets. People would get super expensive/fancy sets of China at their weddings. It was rare you ate on them (if ever). Where are they now? They're worth so little you'd have a hard time giving them away, even in perfect condition.
I miss not having a cell phone being socially acceptable. Sure, you'd have a landline or a cell phone, but there was no expectation you'd be constantly checking it. In the employment world, it's made some sectors a nightmare. I've had jobs where you had 24/7 on-call and were expected to check your phone every hour on the hour until you went to bed, at which point you'd just have to hope your ringer was high enough that you'd hear a mail/text/call and wake up. Maybe a bad example because the employer sucked, but the phone's place in modern culture enabled that.
I miss the old feel of personal websites. I know Neocities is working on this, but it's not the same. Back in the day it wasn't that unusual to be asked if you had a website and what the URL was. It was kind of a cool way to meet someone in a forum or IRL and learn some details about the person through their website, kind of like what modern social media does, but without the aggressive telemetry and monetization. These days I've never even heard of a regular person asking "What's your website?"
This is kind of an oddball one, but bear with me: the laws of physics, particularly Moore's law. Back in the 90s/2000s, every now and then a game would come out that would just crush even the highest end hardware. Games were made to be demanding, but sure enough, a year or two later there was hardware that could run that stuff maxed out at buttery smooth framerates... or as UT2004 called it, the "HOLY ****" setting. The game announcer literally said that when you maxed out your graphics settings. Check it out:
UT 2004 Settings. Seems like these days the jumps in tech are so small that the games that run like crap still run like crap.