I'd say on PC the biggest influential games would be Monkey Island 1 & 2. Before that, Microsoft Adventure and Reader Rabbit was all I knew and I found the PC boring, banal, and over-educational, save for maybe a copy of "Memory Match".
So here's why. The Secret of Monkey Island really showed me what the PC could REALLY do. Here's a game where I had nearly "photorealistic" for the time VGA graphics, a "Sandbox" as they call it now to run around in. You could not die, but you had to solve puzzles to keep from getting bored. The only exception was the music because my sister's weedy little DOS 5.00 equipped 386 had internal speaker only - so the only background music was the theme. This took me to digging around my sister's 1980's record and tape collection. I met A-ha, Mr. Mister, Bon Jovi, Duran Duran, Bryan Adams, Loverboy, Cheap Trick, Kenny Loggins, Miami Sound Machine, Tina Marie, Journey, Shalamar, Karla Bonoff, Marietta, Steve Stevens outside of Billy Idol, and numerous others that way. Literally the Top Gun soundtrack was the soundtrack to SoMI to me. Those songs I listened to playing Monkey Island with the internal speaker are what drew me to want to learn to play bass, synth, and guitar. I still can't go to the Fettucini Bros to this day without hearing Gloria Estefan singing "Hot Summer Nights" - despite it not at all fitting almost getting a concussion for 400ish pieces of eight (in game of course).
Monkey Island 2 was the first game I ever wrote a hint-guide for, for my 25 year old sister, because some of the puzzles in that were quite unfair (particularly the door guy for the wheel game in the alley, and the forest on Dinky Island). I wonder if she still has that somewhere, 🤣. IIRC "The Call" was what I was listening to playing that one.
Console wise, probably Illusion of Gaia and Dragon Warrior series were what got me into RPGs heavily along with Ultima VI for PC - which was the first DOS PC Game I ever owned - I played that game for an entire week while I was stuck at home with PInkeye during/after my 11th birthday. I remember being happy to at least have one eye open to play that game, made me forget I even HAD pinkeye for awhile. I think U6 might have also been why I like GTA and Postal so much because that's how I played it when I was 11 sometimes - once digging my Karma score so low that when Lord British revived me, I was just a dead sprite floating around Brittania, having not atoned for my sins....I have to wonder if Lord British ever considered just turning me into a Candlebra or a piece of cheese to "disarm" my malicious and klepto in-game behavior. 🤣.
Then my friend who had a Mac as a kid, he had Sim City 2000, which introduced me to the Sim series, and turned me into "that guy" who can spend hours upon hours micro-managing and building whatever the sim game is about. Probably the reason I spend all my time in The Sims building houses is a result of years building massive cities with SKURK, only to watch them burn afterward due to imbalance in infrastructure, power, and citizens.