Day I Wrote You Off by Eels is a raw and heartfelt break-up song that delves into the emotions of letting go and moving on from a broken relationship. The key themes of the song include heartache, self-realization, and liberation. It captures the pain of separation but also the sense of relief and empowerment that comes with accepting the end. Poignant moments include the candid expression of the protagonist's anguish and the powerful declaration of independence as they 'write off' their former lover, signifying a significant step towards emotional healing.