The surface meaning of this sentence was: the first time I heard a song, I didn't know its meaning, but the second time I heard it, I understood the emotions of the song and became the person in the song. Since you've already become the person in this song, why listen to this song again? After the song ended, she should be awake. This is a pessimistic ending, telling us not to be addicted to a song or a relationship, to wake up in time and walk out of the shadow of this relationship. It can also tell us to cherish the life in front of us and not to indulge in the beauty of the past because the past can't be changed, and the beauty in front of us is what we can grasp. Therefore, we can reply to this sentence: "Cherish the present and walk out of the shadows."