It's always Double Dash, isn't it? And that's for a reason, I suppose. Double Dash is easily the most 'different' Mario Kart. And that's beyond just the token two drivers gimmick. The way I see it...

It's the acne-riddled, late-adolescent game in the series. Trying to grow onto new hardware that wasn't nearly as restrictive as 64, it got to stretch its legs and try things... but never seemed exactly sure what it was aiming for.

After Double Dash, Nintendo 'figured out' Mario Kart and we got Mario Kart DS. Every game in the main series since then has been a more polished, iterative version of it. MK DS plays more similarly to MK8(DX) than Super Mario Kart plays to 64 and DD plays to DS.

So it's a special game. I'm glad people love it because I love it, too, in a way. I don't really like actually playing it, but I like how different it is. To me the driving isn't great, it's lacking 64's nostalgic simplicity, but its attempts to make the driving deeper were rough around the edges and, really just don't feel good to me. I understand you're supposed to drift - a carryover to the rest of the series - but even that feels slippery and like my cart is only taking mere suggestions from a force like gravity.

But I do love it's dare to be different. While I have an absolute blast playing MK8/DX, it definitely feels more... specific? They knew exactly what they were doing, did it damned well, made a damned game, but it is definitely more of the same. Double Dash threw a ton of stuff at the wall to see what stuck. A lot of it didn't, and most of the stuff that did needed improvement. And, really, sometimes that's the style of party game you're going for. Throw a bunch of stuff together and see what happens. And it happens to still be pretty damn fun... though it's probably not the game in the series I'd play over and over by myself.