one thing i've noticed is when youre playing a song and you click on the album art, and then click the 'X' to remove the song from the playlist because you don't like it, then when the song completes the first song in the playlist starts playing again. i.e. pressing 'X' removes the song from the playlist as expected, but the playlist is re-loaded and the current playing position is lost.

what this means is that it's impossible to build a playlist that you like by removing songs that you don't like.