 The Dude tells Maude he was a roadie for Metallica (qv) on their  (fictional) “Speed of Sound” tour and refers to the band members as  a "bunch of assholes." Metallica themselves were flattered to be  referred to in a Coen Brothers movie, with guitarist  Kirk Hammett (qv) once noting in an interview that theyd tried to  think of a way to incorporate that scene into their live shows.