Rules: just pick 1 and explain why.
I’ve been playing since the NES and despite being from a low income family I had the luck of being able to play and own many consoles over the 3 decades of my life, plus some pc.
If you ask me right now? Resident Evil 4 (2005).
A before and after in gaming, to this day still extremely fun to play even for casuals but 20 years ago it was THE masterpiece. And everyone took notice of it, everyone played it, even players that didn’t cared about resident evil. The gameplay was so good that it got photocopied by everyone right after in the action genre.
Arguably the last big innovator in videogames minus Minecraft and… PUBG (Fortnite did it better I know).
Try to NOT pick your favourite game, that’s a different thing.
I’m tempted to say either The Witcher 3, Grand Theft Auto V, or Metal Gear Solid 5 (if you can look past the fact it’s unfinished).
All three are exceptionally polished, have huge, highly detailed world’s to explore, cinematic moments with blockbuster action scenes, smooth and balanced gameplay, are suitable for gaming noobs and veterans, and has moments to goof off and dick around.
It’s hard not to be biased, though I’ll state I don’t personally like GTAV, I think it’s perhaps too ordinary for my tastes and feels too restrictive in its mission structure.