I loved JM's acting in this second clip. She clearly has a wonderful sense of humor as she tries to hopelessly imitate the other singer. There is so much sensitivity and actual sophistication in the way she handles this scene - with a real sense of self mockery at her attempts to be "peppy" - that I fell in love with her. Much more subtle acting and awareness than I usually imagine in these older formuaic movies.
West Side Story! I teach this every year to 5th and 6th graders and after many years many of them still thank me for introducing them to this movie. I still cry every time those chords start up for "There's a Place for Us" at the end. And when Maria screams out "Don't touch him!" I weep without fail.