Justin Vernon, the singer-songwriter best known as Bon Iver, appeared on Late Night with Jimmy Fallon to perform a special rendition of Bonnie Raitt's "I Can't Make You Love Me," a.k.a. the saddest song in the history of popular music. Accompanied by piano, Vernon sings the entire song in a pained falsetto, selling its hopeless heartbreak while changing the phrasing just enough to flatter his strengths as a vocalist.