What is good riddance?

"Good Riddance (Time of Your Life)" is a song by the American rock band Green Day, released as a single in 1997. It's from their fifth studio album, "Nimrod." The song is distinct from Green Day's typical punk rock sound, featuring a more acoustic and melodic approach. Written by lead vocalist and guitarist Billie Joe Armstrong, the song is introspective, addressing themes of reflection and change. Despite its bittersweet lyrics, it has often been used in celebratory contexts, such as graduations and farewells, due to its catchy and somewhat uplifting melody. The song was a commercial success and is one of Green Day's most popular tracks, showcasing their versatility as a band.