Writer David Benioff said in a BBC interview, "The first time I saw [Edward Norton] on set he pulled back his hair and showed me his widow's peak. In the book, Monty Brogan has a widow's peak, but I hadn't mentioned it in the script. But Edward so wanted to be in character that he wore a prosthetic widow's peak for the entire shoot."
Although Monty's bathroom monologue is similar to the racial stereotype montage in Spike Lee's Do the Right Thing (1989), it is taken almost verbatim from David Benioff's original novel. The only part not from the novel are the references to Osama bin Laden and the 9/11 attack.
Edward Norton's character mentions about wanting to be the "girl in 'X-Men', the one that can walk through walls". Co-stars Anna Paquin, Brian Cox, Aaron Stanford and Dania Ramirez have all starred in the X-Men movies, as Rogue, General Stryker, Pyro, and Callisto respectively. The girl who can walk through walls is called Shadowcat.
During the famous "Rant Scene", Ed Norton curses his father who "sells whiskey to Firemen and cheers the Bronx Bombers". Every patron in that scene was a real Firefighter from Rescue 5 based out of Staten Island, New York. All 11 Firefighters in that scene were killed at the World Trade Center on 9/11/01.
Six actors in this film have also starred in Marvel productions. Edward Norton was in The Incredible Hulk (2008) while Anna Paquin, Brian Cox, Aaron Stanford and Dania Ramierz have all been in an X-Men film as Rogue, General Stryker, Pyro, and Callisto respectively and Rosario Dawson protrays Claire Temple in the Marvel/Netflix shows Daredevil and Jessica Jones.
Spike Lee: [glide] In the scene right after Jacob leaves the bathroom, he is seen motionless with the the background slowly panning out. Spike Lee often places actors on dollies to achieve this effect.
Spike Lee: [basketball] Both Monty and Naturelle played high school basketball; another scene depicts a playground game. Also, Frank is reminded by his boss that they have courtside seats for an upcoming game.