Most people would agree that Mario Kart is most fun when played with others. Although there is a single player mode, Mario Kart is an inherently social game and one that demands competition. I think that this structure provides interesting dynamics between multiple players and between players and CPUs. In my experience, these dynamics arise from two main categories: the relationships between players and the relative skill of the players.
I am a generally competitive person and have been known to yell at a video game from time to time. This yelling only seems to increase when there are other people to blame for my misfortune, rather than the game, or even worse, my lack of skill. This experience is exemplified when playing Mario Kart. When playing with friends, there is nothing more satisfying than laughing as you hit them with a red shell and zoom into first place or yelling at them if they do the same. This experience is one that I believe embodies the spirit of Mario Kart, so much so that it transfers even when not playing with friends in the same room. When playing online against people around the world, or even against CPUs, I experience similar bursts of emotion and yell at those who can't hear me. While I think that these feelings are muted compared to playing with friends, they are still present and characterize my gameplay experience. This is a powerful ability of Mario Kart, and other multiplayer games, to be able to create such a charged multiplayer experience even when not physically playing with others. Because Mario Kart relies so heavily on its competition aspect, players eagerly create their own when none is present. This 'requirement' of the game and subsequent response of the player is so strong that yelling at CPU Waluigi or someone halfway across the world is a satisfying action because it fulfills the multiplayer experience. One caveat of this for me is that I won't play this way around someone I don't know very well. Playing in the same room as a stranger or acquaintance, I won't yell (at the game or at them) and generally have a much calmer gameplay. For me at least, the multiplayer dynamic requires an appropriate closeness or distance to fully manifest.
In addition to one's relationship to the other players, I find that player skill has a large effect in how I play with others. While in the previous paragraph I discussed how CPUs can come to 'be' real players, I likewise find that some players can appear more like CPUs. When playing in the same room as people who are significantly less skilled than me, I sometimes find that the sense of competition among us is gone. If I'm squarely in 2nd place and they are far behind in 12th, I'm more likely to turn my frustration on the CPUs around me and effectively ignore the other player's role in the game, as I often do the CPUs who are not immediately in my area. In a way, the game allows one to humanize the CPUs and "computerize" the people they're playing with. However, in my experience the same isn't true when the roles are reversed. Even when it's hopeless for me to win, and even if it's definitely my own fault, I'm more than happy to yell at my friend who just crossed the finish line a whole 40 seconds before me. I think the most intense dynamics arise when players of similar skill play against one another. In these circumstances, it is likely that your friend is the reason you moved down one place and you just have to yell at them. I, and I think many others would agree, think that these are the most fun rounds of Mario Kart.
I think that these interactions, which I find to be integral to a good game of Mario Kart, are strong evidence supporting Sicart's argument against proceduralism. He summarizes that "For proceduralists, which are after all a class of formalists, the game is the rules." However, this idea of a game breaks in Mario Kart. The rules of the game more or less tell you drive around a track as fast as possible. While this is of course an important part of the game, it does not capture any of the relational aspects brought by the players that become the center of many races. Instead, Sicart's description of play as "a balance between reason and ritual" is more apt here. The rules, the circles around the track, are the "reason." And all of the the competition, yelling, frustration, and arguments are part of the "ritual" of the game. I particularly like the use of "ritual" to describe these non-prescribed aspects of Mario Kart. Although no one says the game has to be played this way, almost all races I have participated in see these same kinds of interactions. These dynamics have become regular and somewhat scared parts of the game and in some ways, a round of Mario Kart feels unsatisfying or incomplete without them.