This article discusses the power of lyrics in music, and how some can become 'rent-free' in a person's head. It talks about how certain lyrics, especially those with deep personal meaning, can stay with a person long after they have heard the song. It suggests that the words can become part of a person's identity, and become a part of their story. It also talks about how re-listening to the song can bring back memories and feelings, and how some songs become intertwined with particular memories or events. Finally, it suggests that when a person is truly moved by a lyric, it can become a part of them forever.