 Stefani had been working on her solo project with Linda Perry . The two penned several songs , including lead single " What You Waiting For ? " , but Stefani found the process difficult , commenting , " It 's humiliating and intimidating even if they 're sweet and excited , because you 're drowning in their creativity . " When the two began working on a song about a deceased friend of Stefani 's , Perry began writing the lyrics and Stefani , feeling that Perry was encroaching on her territory , broke down and left . 
