By December 1972, having recorded "Machine Head", "Made in Japan" and the yet to be released "Who Do We Think We Are" with Deep Purple, Gillan finally decided the workload had driven him to exhaustion. Unlike some band members, he was unhappy about "Made in Japan", and disliked live albums in general. He tended to go into the studio after the rest of the band had recorded and finished the backing tracks, particularly for "Who Do We Think We Are", to lay down his vocals separately. He had been continually at loggerheads with Blackmore, disagreeing about music regularly, which culminated in Gillan writing "Smooth Dancer" about him. While on tour in Dayton, Ohio, he sat down and wrote a resignation letter to the band's managers, stating he intended to leave the band, effective from 30 June 1973.