Whatsername by Green Day is a song reflecting on memory and loss. The song deals with themes of past relationships, nostalgia, and the bittersweet nature of memories. The narrator recalls a girl from his past, reflecting on the moments they shared and the impact she had on him, even though she’s no longer present in his life. Key poignant moments in the song include the chorus where the narrator admits he has forgotten her name but not the memories associated with her. This highlights the tension between forgetting a person and remembering the emotional impact they had. In essence, the song captures the melancholic essence of looking back at past love and the inevitable fading of those memories over time.