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.
The game world is so close to feeling real… the physics and horse handling feel basically perfect. They took their time to make you feel like you were in 19th century America.
That's the problem with asking such a subjective question. What you hate others love. I thought my friends raving about the slow pace of the game were insane. Who would like that. Then I played and fell in love with all of it.
Where you saw a turnoff, plenty more saw enjoyment.