Leo-J, I can understand you not liking the game. I can understand you hating it. But I think it's a very grave mistake to think others are stupid for liking what the game has to offer. I'll therefore offer a small explanation to what seems to you to be weird and stupid behaviour.
Non-gamers often have very little sense of how rigid the rules in games really are. In a game you can never do anything that is against the rules of the game, and you can never go beyond them either. Most games are built on you learning the rules and then exploiting them, or using them. In stealth games for examples, you quickly learn when the enemy can see you and when they can't, and use that to your advantage, making you feel really good about yoruself. A non-gamer would not understand the rules beneath the surface, and would be slightly confounded at what's happening instead.
Just Dance's the rules seem to be rather lax and imprecise, which annoys you as a gamer. The Non-gamers, being new to the rigid rules of gaming, finds this absolutely charming instead. Since the understanding of the rules is lacking, the lax and imprecise rules instead seem inviting and friendly. Instead of looking at it as a game, with all the preconceptions we all have about that term, they see something that grades your dancemoves.
For them, it isn't as much about how they interact with the game as how the game interacts with them. And it's telling them to dance, how to dance, and that they are succeeding in doing so. THAT is not something they have ever experienced before, so it's a new and happy feeling to do it. Not to mention that they probably enjoy to dance, and that they love watching their friends go at it as well.
So, in short, the system of rules that make up games scare non-gamers away, while it offers great opportunities for you. When that system is broken up, you feel lost but the non-gamer feels at home. Plus, they probably enjoy dancing more than you think you do.
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