Paul McCartney describes his writing process for writing emotional songs, so Jimmy gets him in a bad enough mood to make up an angry song about him on the spot. Subscribe NOW to The Tonight Show Starring Jimmy Fallon: http://bit.ly/1nwT1aN Watch The Tonight Show Starring Jimmy Fallon Weeknights 11:35/10:35c Get more Jimmy Fallon: Follow Jimmy: http://Twitter.com/JimmyFallon Like Jimmy: https://Facebook.com/JimmyFallon Get more The Tonight Show Starring Jimmy Fallon: Follow The Tonight Show: http://Twitter.com/FallonTonight Like The Tonight Show: https://Facebook.com/FallonTonight The Tonight Show Tumblr: http://fallontonight.tumblr.com/ Get more NBC: NBC YouTube: http://bit.ly/1dM1qBH Like NBC: http://Facebook.com/NBC Follow NBC: http://Twitter.com/NBC NBC Tumblr: http://nbctv.tumblr.com/ The Tonight Show Starring Jimmy Fallon features hilarious highlights from the show including: comedy sketches, music parodies, celebrity interviews, ridiculous games, and, of course, Jimmy's Thank You Notes and hashtags! You'll also find behind the scenes videos and other great web exclusives. http://www.youtube.com/fallontonight #FallonTonight #PaulMcCartney #McCartneyOnFallon