Quod Libet, the Perfect Music Player
One of my pet peeves when it comes to software are Music Players.
Music tastes are entirely subjective, yet the vast majority of Music Players are heavily opinionated in how we consume music. They put Albums and Artists as the main breakdowns with the option to manually create playlists. Most are bloated with other features like Lyrics, Wikipedia entries and everything else unrelated to playing music. Their interfaces are rigid and inconsistent. It's all just an extremely restricted environment, a far cry from the massive variety of music that's out there to listen to.