When you have an entire playlist queued up, as you go from track to track there’s a little pause. This is because one track ends and the next track is loaded before it can start playing again. It’d be nice if the next track were pre-loaded as the current one is close to finishing so that there’s no delay.
This is especially nice with albums where all the tracks are meant to be heard together as one huge song.
I’ve also seen it before where the “transition” is configurable, for example a “fade” where the end of a tracks is played quieter as it transitions to the next song.