The controversy erupted over a scene in which Ben Affleck's character, Nick Dunne, was supposed to wear a New York Yankees cap while at an airport. Affleck, a proud Bostonian, stood his ground against Fincher's vision, stating,
"David, I love you, I would do anything for you. But I will not wear a Yankees hat."
This passionate refusal highlighted the actor's loyalty to his Boston roots and his aversion to wearing the cap of a rival baseball team.

After some negotiation, the two ultimately agreed on a compromise: Affleck's character would don a New York Mets cap instead. Fincher humorously remarked on the situation in the audio commentary of the DVD, calling Affleck's insistence "entirely unprofessional." This incident not only showcased the strong personalities involved in the film's production but also illustrated the lengths to which actors will go to maintain their personal beliefs and identities, even in the face of a director's creative vision.
Ultimately, the resolution of this cap debate was just one of many challenges faced during the making of Gone Girl, a film that would go on to captivate audiences with its intricate storytelling and complex characters. The behind-the-scenes dynamics serve as a reminder of the collaborative yet sometimes contentious nature of filmmaking.