I’m not necessarily talking about moment-to-moment gameplay or mechanics (though I could see some interesting points being made about, for example, RTS gameplay or RPG character building influence how you approached “strategy” in your own life).
What I’m trying to get at are the games you felt really had something to say.
For example, while I’m by no means the biggest fan (only ever played 2 and V), playing MGS V recently (and catching up on the background a bit) has created this sense in me, and I wondered where else one might have experienced that from vidya
Kreia has some great quotes.
Also Deus Ex
The second kotor had flaws but Kreia has some great quotes.
KotOR (especially 2, which I played first) took Star Wars from a kind of series of “bubbles connected by plot threads” (how I saw the movies) to being able to see the various bits of media as “slices” taken out of a “real” universe, which I always loved it for - everything seemed more grounded
Kreia is one of the best-written Star Wars charachters in any medium, and the one that really shows off what's possible with a made-up group of people that amount to space wizards with laser swords.
Valkorian is probably another, if only for the sheer ham the man brings to the table that you can't help but take seriously. He's one of the few charachters who could seriously utter the words 'I am a God' and you can't help but nod in agreement.