I liked RBY, but I loved GSC. Gold was and still is my favorite Pokemon game, probably heavily due to nostalgia. I enjoyed playing Red, and many of my favorite Pokemon come from gen I, but I didn't like the glitchiness. Unlike Red, which I got later than most of my friends, I was the first person I knew to get Gold, and it was really neat to discover Johto (and then, surprisingly, to rediscover Kanto) with my Totodile. Gold also fixed many of Red's flaws, and just seemed to much more expansive than Red.
I really grew as a Pokemon player through Gold. I came to the game as a Blastoise solo runner (like many kids; at least mine knew Bite, rather than only water moves). I began Gold as a Totodile soloist (never evolved it because I didn't like the way Croconaw and Feraligatr looked). I finished my experience with a team, a completed Pokedex, completed Stadium games, and a rudimentary understanding of competitive battling. Sure, my team was the antithesis of balanced, and isn't the sort of thing I would use competitively today (Totodile, Blastoise, Quagsire, Pikachu, and Noctowl, plus an extra rotating slot for whatever I needed to train in-game), but I loved it, and it helped me move beyond my Red play style. Overall, even though I became much more involved in making competitive teams and such later, Gold marked the biggest leap in my playing ability, attitude towards the Pokemon games, and general Pokemon experience.
Without RBY, the start of my Pokemon journey would have been different, and I might never have gotten into the franchise at all. But without GSC, I would probably have been trapped in my gen I mindset, and I might never have become as obsessed with Pokemon as I ultimately have. On the whole, I think Pokemon has played a positive role in my life over the past fifteen years, so I'm glad I got started with Red when I did, and I'm glad I had the chance to play and enjoy Gold. Even though my original file lasted less than six years before the battery died, I created lifelong memories during that time, for which I am extremely grateful.