The song "Say Goodbye" by Unknown Brain and Marvin Divine tells the story of a toxic relationship and the narrator's decision to end it. The lyrics describe their realization that the person they were with was a manipulator, playing games and spreading rumors about their private conversations. The narrator decides to distance themselves from this toxic behavior and focus on themselves. Despite the breakup, the narrator expresses that their life is now better and they are happy without the other person. They acknowledge that the grass is not always greener on the other side and the person who hurt them will eventually realize their mistakes. The chorus emphasizes the narrator's decision to say goodbye to the negative influences in their life. Overall, the song highlights the importance of recognizing toxic relationships and choosing to prioritize one's own happiness and well-being.