Best: "Let It Go" ('Frozen,' 2013)
This Disney fable is the highest-grossing animated film of all time, and it has three little words to thank for it. Written by the wife-and-husband team of Kristen Anderson-Lopez and Robert Lopez, the song's message of self-acceptance and empowerment resonated strongly with co-director/screenwriter Jennifer Lee; she and her team ended up reimagining the whole movie around it, changing "snow queen" Elsa from a villain to a sympathetic co-protagonist. The result is a showstopping showcase for the talents of both singer Idina Menzel and the animating team, unleashing Elsa's powers like something between a superhero origin story and a Pride parade. One of the best songs in Disney's decades-long repertoire, it imprinted itself on the consciousness of a generation faster than you can say "The cold never bothered me anyway."