The act of "favoriting" a song is so commonplace in entertainment driven music apps, that's it's a fairly common question here at Focus@Will. However, we have found that if a song is something you really like or really dislike the underlying result is the same - you have noticed it. And when you notice specific songs in the music stream you are not focusing on the task at hand. Ideally, you shouldn't notice the individual pieces of music at all. The idea here is not to be entertained, it's to use the service as a tool to help you get work done.