"Party Favor" by Billie Eilish is a song about a toxic and one-sided relationship. The narrator of the song is addressing their partner, who is not fully invested in the relationship and only wants what they can't have. The song starts with the narrator leaving a message, asking their partner to call back or make time for a serious conversation. However, they then suggest forgetting about it, as they anticipate their partner might have blocked their number. The lyrics then express frustration towards their partner's behavior. The narrator feels that their partner only wants them when they cannot have them. They threaten to call the cops or the partner's dad if their unwanted advances continue. They express their disappointment in having to confront these issues on the partner's birthday, and sarcastically wish them a happy birthday. The second verse acknowledges that the relationship could have been better, but emphasizes that they cannot change the circumstances. The narrator compares understanding the relationship to reading a book backward, where the wrong words are singled out and misinterpreted. They believe their partner hears what they want to hear, misinterpreting the narrator's intentions. Overall, "Party Favor" explores the unbalanced and frustrating nature of a relationship where one person is not fully committed. The lyrics convey a sense of resentment towards the partner's behavior and a desire to break free from being treated as just a party favor.