 " Crash " is an electroclash song that uses automobile metaphors to describe a relationship . " The Real Thing " was described as a vintage Europop song , and features guest appearances from New Order vocalist Bernard Sumner and bassist Peter Hook . The next track , the synthpop song " Serious " , drew comparisons to Madonna 's work during the early 1980s . A music video was produced for the song , but it was never officially released , although a snippet of the video surfaced on YouTube in October 2006 . " Danger Zone " , an electro @-@ rock song , was widely interpreted to be about Stefani 's husband Gavin Rossdale having an illegitimate daughter ; however , the song had been written before the discovery . The closing track " Long Way to Go " is an outtake from André 3000 's album The Love Below ( 2003 ) . The song discusses interracial dating and uses a sample of Martin Luther King 's " I Have a Dream " speech . 
