My top rated

My very carefully chosen five star playlist has been infiltrated by a load of tedious rubbish that I never listen to. It's so embarrassing - I'm know at parties for my playlists and now they're a joke. I've searched these forums and people say if you give an album a rating (which I don't think I have) it adds grey stars to your top rated playlist. But songs that I don't even like are showing up on the 'My top rated' playlist with five grey stars next to them. I only want the blue stared tracks that I've selected myself in there. I'm starting to think the only way to manage playlists is to drag and drop tracks into them but when I do this the tracks are duplicated on my phone.