[shabgzer]

What works for me sometimes is to search for other people's playlists by using the keyword of a genre or a particular mood I'm after. Filter out the Spotify-generated ones of course. Usually after 20 results you start getting to the good stuff.

Also I've had some success doing collaborative playlists with random friends / acquaintances. A song I added would give them an idea for a song, and we take turns that way. A lot of it is rubbish, though. :-)

What would work even better is if Spotify had a way to search playlists containing a specific song!