This is based on opinion. Please don't list it on a work's trope example list.
Tear Jerker / Radio Rebel
Stacy looking at herself in the mirror and encouraging herself that no matter what happens, she's a Queen. Despite how mean she's been to Tara, you just have to feel for her in this scene. She's invested herself so completely in becoming Prom Queen that she doesn't know what she'll do if she loses. Easily Forgiven or not, you actually feel good when she makes her Heel–Face Turn and gets the crown.
When Tara looks like she's about to cry because she's getting so many calls about prom being canceled, it's really hard not to feel sorry for her.