'The Break-Up'

How it ends: With Vince Vaughn and Jennifer Aniston randomly meeting on the street months after breaking up.
How it was supposed to end: Originally, they were just going to split and be done with it, but the movie happened to coincide with Aniston's real-life breakup with Brad Pitt after he left her for Angelina Jolie. Producers didn't want her character to get jilted on the big screen too, so they re-shot the ending to include a more ambiguous finale that suggested there was hope for reconciliation.