At the conclusion of filming in Atlanta, furniture and props from the set were donated to the Furniture Bank of Metro Atlanta, a charity that gives away free furniture to people moving into stable housing from homelessness and domestic violence.
NBA All-Star Jimmy Butler from the Chicago Bulls was cast in the movie due to his close relationship with actor Mark Wahlberg, who thought Butler would be a nice choice given that the setting of the film is Chicago.
The trivia item below may give away important plot points.
During the scene where Carol is using her self-defense skills against the guards in the club to get to Clay, Josh mocks the guard saying that Carol is filled with nothing but "salad and Smart Water" and can still take him down. Ironically, Jennifer Aniston (who plays Carol in the film) is a spokesperson for Smart Water in real life. This was intentional, as Aniston is a spokesperson for Smart Water.