Spotify's invisible shuffle toggle
The best design is invisible.
In most music apps, I inevitably leave shuffle mode on for longer than I'd like. I might enable it when listening to a playlist. When I later listen to an album, I might get halfway through before realizing shuffle is still enabled and the songs are playing out of order.
This never seems to happen on Spotify, however. Spotify seems to automatically disable shuffle whenever it's no longer wanted. I don't know what heuristic Spotify uses to determine when shuffle should be disabled, and as a user, I don't really need to care. All I know is that shuffle never seems to be on when it shouldn't be.