I once knew a man who played the piano but was tone-deaf. The man would spread out his sheet music before him and begin plunking along. The notes sounded OK, but the music lacked heart, because although he was able to mechanically play the notes quite well, he couldn't hear them. Listening to his music was like listening to a musician who who had no heart for what he plays.
A musician who plays from the heart hears the music as he plays, and he plays it with love. He is able to do this because, somewhere, at some point, something opened up his heart center. This is a place where this very special, unexplainable love comes from.
It's interesting to note that once this door to love has been opened, even though it may almost close again, some degree of the love will somehow manage to come through.