This is a fantastic insert song from an anime called WorldEnd for short (which is also fantastic in its own rights, albeit notoriously underrated). It's very rare for music to have the slightest degree of emotion, but the composer Tetsuya Kato has nailed just that to align with the affectionate moments in the story. In-coincidentally, there's an abundance of that because the anime takes time to help the characters grow and overcome their respective hardships and inhibitions. Season 2, please.