I simply adore Super Mario Kart. I have sunk more hours into this game than any other game in the series, easily. It's not like it was a super deep game, or had tons of unlockables or anything like newer games have, but back then, as a kid, it was the end all to be all for racing games. My friends and I would play relentlessly, usually focusing on being the absolute king of the kart, which would involved placing first in the entire cup of our choice. Back then, before the threat of blue turtle shells, one could easily dominate the game with patience, practice and a lot of skills. Of course, I say "easily" tongue-and-cheek.
Who remembers the feeling of timing the start-light just perfectly, so that you get that immediate boost of speed and power from the start line? Figuring out that cool little trick was the equivalent of finding a warp whistle in Super Mario Bros. 3, or discovering the "Rock the Turtle" technique in the original Super Mario Bros. game. Little tricks that Nintendo put in their games to make the players feel awesome upon discovery of them. Nintendo always knows how to make their gamers smile.
Also, the battle mode in this game is ridiculously fun, especially considering how simple the mode is. Drive around and try to pop each others' balloons - no more, nothing less. But for some reason, no matter how simplistic and straight forward it may appear on paper, once you start playing it with friends you realize how awesome it is. That mode alone is responsible for probably a third of the game time I've had with this game over the years, easily.
Overall, this game is an all-time classic and a timeless display of gaming at its best. Apparently I'm not the only one to think that, as this game went on to sell more copies than any other game for the Super Nintendo. Over the years, it is the golden example of the kart-racing genre, as many games have tried to emulate what Nintendo created over the years, so mild success. Yet no one has come close to duplicating what Super Mario Kart exactly - not even Nintendo, all these years later.