Why isn't repetitive music boring to listen to?

A Quora user asks why we don't get bored when listening to repetitive music. This is related to the equally interesting question of why we can play repetitive music without getting bored. Why is there so much joy in repetition?

Humans are pattern recognizers. You'd think that once you'd learned the pattern of a repetitive piece of music, it would quickly get boring, and then annoying. Sometimes, that is in fact what happens. I don't enjoy Philip Glass' music; it makes me feel like I'm stuck in the mind of someone with severe obsessive-compulsive disorder. But I adore James Brown and Fela Kuti, and my iTunes library is stuffed with loop-based hip-hop and electronica. So what's going on? Why do I find Philip Glass annoying, but not James Brown? The best answer I've found is in this paper: Butterfield, M. (2010). The Power of Anacrusis: Engendered Feeling in Groove-Based Musics. Music Theory Online, 12 (4). Butterfield argues that we don't hear each repetition as an instance of mechanical reproduction. Instead, we experience the groove as a process, with each iteration creating suspense. We're constantly asking ourselves: "Will this time through the pattern lead to another repetition, or will there be a break in the pattern?" Butterfield describes a groove as a present that is “continually being created anew.” Each repetition gains particularity from our memory of the immediate past and our expectations for the future. Little deviations from the expected pattern add interest to a groove. There's tension between the expected identical repetition and the imperfections of the actual performance. This is why a hip-hop breakbeat sampled from a live performance can be so much more exciting than a drum machine pattern quantized exactly to the grid. The best production software lets you quantize your MIDI events to grooves derived from samples, rather than just straight metronomic time. In order for a repetitive groove to be exciting, it has to create a feeling of anticipation. The materials of the groove have to match the listener's particular appetite for harmonic and rhythmic complexity, and for certain timbres and stylistic gestures. I find each bar of James Brown gratifying, and each bar of Philip Glass boring. I'm eager to find out what's going to happen in the next bar of James Brown, whereas I couldn't care less what's going to happen in the next bar of Philip Glass. A person with a different cultural background and different tastes from mine might feel exactly the opposite. Both of us are right.