Continuity mistake: In the very beginning scene when the Treblemakers are singing "Please Don't Stop the Music", they do not have on sunglasses, then it goes to the commentators. When it goes back to the Trebles, they are wearing sunglasses, then a few seconds later they aren't again.
Continuity mistake: In the picnic scene, there is one extra in the background with a blue shirt and jean shorts that walks by three times.
Continuity mistake: When the Bellas are performing at the frat party, Chloe briefly turns her head to show that her hair is in an elaborate updo. In the scene immediately following that scene, Chloe's hairstyle changes to a bun pinned to the back of her head.
Continuity mistake: When Beca arrives during the fight scene you can see Denise behind Fat Amy and Chloe moved to approach Lily twice in between scenes.
Continuity mistake: During the shower scene where Beca and Chloe song Titanium, Beca begins the shower wearing gauged spike earrings but when Chloe startles her they are regular silver earrings and they remain that way for the rest of the scene.
Continuity mistake: The extras directly behind Chloe and Aubrey in the auditioning scene keep changing or disappearing, especially when Beca arrives.
Continuity mistake: At the very start of the film when Bumper is telling the Bellas that they are "awesome-ly horrible, I hate you, kill yourselves, sisters before misters," one of the members from the Trebles walking off stage behind him walks by twice in the same direction.
Answer: It wasn't just that she sang a song he likes, she sang arguably the most well-known song from his favorite film in front of a huge crowd of people. It was a public, heartfelt apology rather than the abrupt, private apology she gave earlier.
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