Castaway by Green Day dives into themes of alienation, disillusionment, and the search for identity. The song reflects the feelings of being lost and isolated in a chaotic world. It's a punk rock anthem that conveys a sense of rebellion against societal norms and the feeling of not fitting in. The lyrics paint a picture of a person who feels like a castaway, drifting away from what is expected of them and seeking their own path. Key moments include the chorus, where the repetition of 'Castaway' emphasizes the feeling of being adrift and alone.