to elaborate on this thought slightly: saying that, to some extent, you can vary something 'perfect' without ruining it might seem obvious and beside the point (or alternatively, obviously wrong). but it's exciting when you realize that it might be possible to unite musical directions that seem like opposites, because it changes your conception of what's possible with the medium. (in other words, it's exciting to think that what seems like an "either/or" situation might actually be a "plus/and" one.) and to me, variation certainly has an appeal of its own--so the idea that you can repeat the best part and change it at the same time is more interesting/consequential than it might initially seem.repeating something with no changes can be great of course, but maybe you can add some degree of variation without losing the 'stay on it' appeal you're talking about? guess i'm thinking of how acid house or dub techno will be built around the repetition of one motif that gets filtered, sent through reverb, etc. in different ways without its basic character really changing--or even how old delta blues musicians will play the same riff over and over slightly differently each time. (there are probably a lot of relatively minimalist styles of music that wouldn't qualify though.)
idk, just wonder if it's possible to the combine the 'repeat the best part' ethos of dance music with the 'river-like' flux possible with generative music to an extent.