I started early enough that I don’t really know other than that they were fascinating and scary and mysterious, especially as 3D games came in, in the late 1980s, which gave you these amazing worlds to explore.
Two things I think have always meant the most for me in games:
World to explore. This rarer now. Fewer games really give you this, but it’s still a factor. I love games where there’s stuff to find and explore and wander around and talk to NPCs and so on.
The opportunity to play strategic or tactical games without hundreds of quid of minis or hours of setup and tidying up, and/or without other players.
Much later, after playing a lot of different games, I started enjoying games about progression and efficiency and builds and so on. This was definitely an acquired taste, and I can basically remembering acquiring it - it was Diablo 2’s fault. When I first played D2, I played it as an action-y CRPG. Played through once, sort of roleplaying my character, and was mystified by the idea that I might want to play it on a higher difficulty setting, but the same game again.
My then-GF, now-wife, though, she loved D2, and she got to play it in a different way, racing through the levels. Saving, not spending points. Trading for gear. Building a character which was effective against ever-tougher enemies and so on. I really got into that, and I never got out completely - I still really enjoy games like that (Path of Exile being a prime exemplar).
I had a phase where I really loved multiplayer shooters, too, in the QuakeWorld era, and was really disgustingly good at them by normal standards (I finally played against a semi-pro regularly a couple of years later and that taught me I wasn’t actually very good at all, though he kept saying he was impressed - still it was like a 1:8 kill ratio in his favour almost every time - but I did learn a lot). It didn’t last though, as the thrill of victory always seemed a little empty compared to the thrill of exploration, or a well-executed plan (and in that era, few people had plans in these games!).
Earlier too I’d really enjoyed fighting games, but once I got to good at Street Fighter 2, Darkstalkers/Vampire Savior and so on that I could beat everyone I knew, it too seemed pretty hollow. Street Fighter Alpha 3 was absolutely the apex fighting game for me, in terms of fun. It’s astonishing but I still somehow have all the reflex memory to do fireballs and dragon punches and so on without thinking. Oddly I later really enjoyed less-well-designed fighters when button-mashing did well, because I could actually have real fun with my friends on those - this isn’t meant as a humble-brag - I was only good because I played so much and owned the games. But I’d rather play a game where there’s an element of randomness and skill isn’t everything, when playing with friends at least.
MMOs I loved very much for the world-exploration elements. EQ absolutely blew my mind in 1999. Like seriously I was never quite the same after playing that. DAoC had the most wonderfully explorable world, somehow the contours of the terrain and visual style (as well as the themes) really spoke to me in a way no MMO before or since quite has. WoW has always been a bit too extremely theme park, but still has some wonderful vistas and moments, and later offered the sort of build-and-efficiency play I had enjoyed. Wrath of the Lich King had perhaps the best balance for me - a world fun to explore, systems sufficiently interesting, and even some multiplayer PvP fun which had tactical elements.
What really made them great, though, was the people (I played DAoC with some really great people, particularly), and WoW represented the end of an era for that, by drawing in tons of people who had no interest in MMOs as worlds, no interest in RP (not even to observe or even tolerate), and so on. It was, oddly, a narrower audience that came to dominate, despite the larger numbers. In most MMOs, and in WoW in 2004-5, the audience was very broad - ages from 10-65, 40% or more female, skill levels at games from non-existent to expert, and so on. But as more and more people joined WoW, they were increasingly male, increasingly aged 16-26, and increasingly focused on solely “playing really well” (which was often cargo-cult nonsense) and winning and achieving to the exclusion of all else. WoW kept operating that way until at least 2012, too (though the worst years for it were probably 2010/2011), before so much of that audience had either aged out or matured a bit, that things started to calm down.
It’s interesting that most of the games I like now, I would have liked or loved when I was say, 16, but a lot of the games I enjoyed from sort of 19-22 I now find rather tedious. The main issue now is finding enough time - I don’t have kids so I have more time than most, but there are still limits.
As an aside I should note that my first love remains pen and paper RPGs - if I had to choose between them and computer games, I’d pick them, in a heartbeat.
That’s certainly how I remember it being when I was a pre-teen, so I’m not surprised to hear it’s still that way. I know that it wasn’t until I was 10 that I really started seeing how fascinating games could be, especially the worlds you could explore.