Because you've been exposed to Western tonal music, you know after a certain chord sequence what the next possibilities are. Your brain has compiled a statistical map of which ones are most likely and least likely. If the song keeps hitting the most likely notes, you'll get bored, and if it's always the least likely ones, you'll get irritated.

There's an ancient connection between movement and music. Most languages don't make a distinction between the words 'music' and 'dance.' And we can see that in the brain. When people are lying perfectly still but listening to music, the neurons in the motor cortex are firing.

Some people like very predictable melodies, and others prefer the less likely notes.

Daniel Levitin Quotes