It has a nostalgic, emotional response with me. I'm typically quick to call it one of my favorite games ever for that reason, despite nearly every subsequent follow-up surpassing it in both QoL and balancing.
It's got some problems, but I just get feelings for it.
On it's own it's a great yet flawed game that helped lay the foundation for an entire subgenre of video games, but the sole reason it earns a top-five GOAT spot for me is the nostalgia I feel over following the breadcrumb trail to unlock the Reverse Castle. I had owned the game for a couple years, 'beating' the game by killing Ricther and always feeling unfulfilled by it - I'd heard one or two rumors from gaming magazines about the RC, but I always assumed it was just a myth. Then one day I happened to stumble upon a section of the map I'd somehow never managed to explore before (the area in the Underground Caverns that leads to your confrontation with the Succubus), and it dawned on me that maybe there is a lot more to this game than I originally expected. I slowly unlocked clue after clue, getting more and more excited with each one, until finally the mystery unraveled completely and the Reverse Castle materialized.
It was one of the most rewarding feelings I've ever felt in a video game; didn't hurt that most of my friends had played the game, and I was the only one who'd ever discovered this. This was around the time where I was convinced that (FF7 spoilers) there was some trick, trail of clues, or secret event hidden in the game that would allow you to revive Aeris; obviously this left me disappointed, so to have a game actually pay off in that regard as majorly as SotN did was a truly remarkable experience. It's also a feeling that would be almost impossible to recreate nowadays, even discounting the fact that I'm older and more jaded; the Internet would not allow something like the Reverse Castle to remain a myth-caliber secret for longer than a day, and it's very unlikely that a major developer would hide half a game's content behind a very esoteric trail of breadcrumbs like SotN did.
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Simple questions deserve long-winded answers that no one will bother to read.