Novelty effect is strong, but there might be a u-shape there. Have you ever tried to get past the valley?

I really enjoyed Spotify and had many play-lists with my favorite music. But when the discovery of new music declined and I got bored with my play-lists I closed the account and have never opened it again.

The curve never go up, but with some songs it have flattened and those are my favorites. But it has more to to with the feelings associated to those pieces then the music itself.