Whats the most popular song for Fall Out Boy?

The most popular song by Fall Out Boy is "Sugar, We're Goin Down". The song was released in 2005 as the lead single from their second studio album, "From Under the Cork Tree". It reached number eight on the Billboard Hot 100 chart in the United States and was certified double platinum by the Recording Industry Association of America (RIAA). The song has been praised for its catchy melody and upbeat lyrics, and has become one of the band's most recognizable hits.