Goofs

When Robert De Niro first enters, he is wearing Ray Ban sunglasses. In a shot from behind, his glasses have clear lenses. Seconds later, he is in Ray Bans again.

When Joy is pressured by her parents to sign the bankruptcy papers, they bring in a Notary Public, and she signs one document. In reality, a bankruptcy petition is usually at least 50-100 pages long, and in addition to requiring several signatures, it does not require the services of a notary.

Stacked on top of the TV in Terri's bedroom are VHS cassettes and cassette boxes that are much bigger than a VHS cassette. These boxes are the type used to store the large 90-minute version of Betacam SP tapes, a professional videotape format commonly used in television production and broadcasting. The equipment used to play back this kind of tape can be seen in the film when Joy takes the telephone call inside the QVC control room.

In the scene at the California warehouse where LAPD is called, the officers are wearing leather belts/gear with a basket weave pattern. Though the basket weave pattern is prevalent in law enforcement, the Los Angeles Police Department wears leather gear with with a plain surface and no stamping.

Joy's home phone service is disconnected because she did not pay the bill on time. In the previous scene, she called QVC on the same phone.

The character mispronounced Lancaster, PA, the way it is pronounced in Pennsylvania (locals pronounce it Lankister).

In the Dallas hotel bedroom scene, when the man has entered the room the door opens further to let the camera crew in.

At around 1 hour 30 minutes in Joy is firing a rifle with no eye or hearing protection.

The television cameras seen in the background at QVC weren't released until a few years after the events of the film take place. These cameras are also shown with LCD teleprompters, which weren't manufactured until the early 2000's.

The yacht featured in the film, a Jeanneau Sun Odyssey DS, did not enter production until the late 2000s.

The cab that pulls up during the funeral has a phone number with a 631 area code, which was first used in 1999.

At the Dallas hotel, a Santander Bank is in the background. Santander started in the US in 2013, and its branches are in the northeast, not Texas.

During the family discussion with the patent attorney at their home, Joy's daughter is playing with an "A" shaped bell/rattle toy that is a current toy on Amazon as part of the B. Parum Pum Pum Drum Set, available in 2016 - not available 30 years earlier as depicted in the film.

QVC is said to be in Lancaster, PA, and Amish buggy drivers are shown on a winding back road. It's actually in West Chester, just outside Philadelphia.