As the B-side to "Can't Buy Me Love," "You Can't Do That" was a worthy companion to the more well-known hit, particularly as it was also one of the Beatles' grittiest and hardest-rocking early originals. The track was introduced by a ringing, circular George Harrison guitar lick that marked the first time he played 12-string electric guitar on a Beatles recording -- an innovation that would figure strongly not just in the Beatles' mid-'60s records, but also in the development of folk-rock. Rhythmically the song has a funkier, more soulful beat than anything else the Beatles had previously done, perhaps sparked by increased exposure to American soul music as the group began to tour in the U.S. John Lennon, in fact, specifically cited Wilson Pickett as an inspiration for the song, although since Pickett had barely begun to record under his own name when "You Can't Do That" was written in early 1964, one wonders if Lennon was influenced by Pickett only in hindsight. The song had no shortage of dynamite hooks, particularly the insistent stuttering beats at the end of each verse and bridge, the thrilling soulful responsive harmonies that answer Lennon's lead vocal, and the dramatic rising harmony vocals that accompany Lennon on the bridge. Lennon lets loose with one of his all-time great screams to launch the instrumental break, in which he makes his debut as a lead guitarist on a Beatles record, with crunchy, frenetic riffing that suits the tune well. Listen also for the very end, in which a reprise of the principal 12-string guitar riff suddenly slows to a crawl for the last three notes. Lyrically this is one of the toughest Lennon-McCartney songs, principally written by Lennon, and verging almost on misogyny in its threats to leave a girl if she so much as talks to another guy. There's an underlying note of insecurity, however, in his laments that others will laugh in his face if they see her acting the way she does. "You Can't Do That" was honored with a most unusual cover version by Nilsson a few years later on his debut album, in which he did not so much sing "You Can't Do That" as use its main motifs for the body of a track which interwove brief phrases from other Beatles classics like "Can't Buy Me Love," "Day Tripper," "You're Going to Lose That Girl," and "Drive My Car."