This scene will probably go down as my favorite one. Lyrically alone it's worth it, just listening to the contrasting voices of both sisters ("I'm such a fool, I can't be free" / "For the first time in forever, you don't have to be afraid"). Also Elsa's subtle look tempting to go back with Anna only to reject her again, and Anna without realizing is pushing her sister to, once again, hurt her with her powers. Also the way Elsa turns to the ice mirror when she says "There's so much fear!" or how she says she can't control the curse, looking up, presumably towards her parents. There's just so much that is right in this scene. I'm completely in love with it.