Maybe it's because it was the first one I played, but something about the 2d aspect of this game gripped me. I don't have the same love for the games that came after it, the 3d graphics somehow take me out of the historical element.
The fact that in the older games you are basically playing on a map, gives off this almost board-game feeling that is cosy and immersive. (I know that civ was inspired by a board game)
Playing civ3 as a kid really made me feel like I was in whatever era I was playing at. Still remember those jazz fusion tracks especially.
My best memories of playing Civilization III?
My only memory of Civ3 was me going "ehhhh, this is too complicated" and going back to Sid Meier's Alpha Centauri!
Now Civ II, that was the game! ...but I didn't play it that much after I got SMAC.
...I've been slowly trying to learn Civilization VI, only because Turtles are apparently a Thing! 😄🐢 Didn't buy Civilization VII because Turtles Weren't A Thing ☹️.
SMAC was honestly more complicated than Civ III, but it was so good that it didn't matter!