The studio almost replaced Jason Mewes ("Jay") with Seth Green. Kevin Smith insisted that Mewes should play Jay, but the studio made Smith take auditions for the role. Breckin Meyer also auditioned. In the end, all concerned agreed that Mewes was right for the part.
Stan Lee can be seen looking to his left or right repeatedly while talking with Brodie. This is so he can see his cue cards - not being a trained actor, memorizing lines was very difficult for him. Jeremy London, on the other hand, despite being an experienced actor, forgot his lines repeatedly.
If you pay attention to the use of Brodie's hand after his 'stink palm' stunt on Svenning, not only does he touch Quint, Tricia, Jay, and Gil Hick's shoulders with it, he also touches comics at the flea market, his other hand as well as his face at the psychic, punches Roddy and Hamilton with it, holds the microphone with it, and also stink palms his hero, Stan Lee. Twice.
Brodie's comic book collection seen in the movie was actually director Kevin Smith's collection at the time (which has grown considerably since). The collection is what Smith was able to purchase back after selling his original collection to finance production of Clerks (1994).
When Renee (Shannen Doherty) runs to tell Jay and Silent Bob that Brodie and T.S. are being arrested, Ethan Suplee (Willam) says, "Brenda?" - a joke reference to Doherty's character on Beverly Hills, 90210 (1990). The exchange wasn't in the script, but rather, Suplee was told to say this by Smith before the scene was shot, and so was Doherty. However, Suplee wasn't told that she would respond, so his reaction is genuine.
The content of the dialogue between Quint and Brodie about whether Superman would be able to have sex and/or a baby with a non-superpowered woman is taken from a classic 1971 essay by science fiction author Larry Niven called "Man of Steel, Woman of Kleenex."
Stan Lee initially did not want to be in the film as himself. He felt the dialogue weren't things he would say. Kevin Smith responded that it was just pretend to which Lee replied, "Okay Spider-Friend".
Shawnee Smith came in to audition for a role. According to director Kevin Smith, she was very rude and mocked the screenplay. After Shawnee Smith left, casting director Don Phillips apologized for her behavior.
One of the game show contestants is named "Gill Hicks" (played by Brian O'Halloran), a reference to Dante Hicks (played by O'Halloran in many of the other View Askewniverse movies). Presumably they are brothers.
According to Kevin Smith, another actor auditioned for, and eventually received, the lead role of Brodie. On the first day of shooting his scenes, the unnamed actor "broke down" and was unable to give the same performance that had earned him the role. The actor was then replaced by Jason Lee.
During the Batman homage as Jay and Bob escape from La Fours, the belting attached to Kevin Smith slipped. The crane refused to start (someone had shut it off), and the key could not be located, nearly resulting in a possibly lethal fall.
While shopping, Rene Mosier (Shannen Doherty) is seen wearing at least three different outfits. Doherty had a clause in her contract that she could keep everything her character wore, so came up with the plan that her character should wear everything she bought on her shopping trip.
In the scene where Jay and Silent Bob are hiding in the bookstore, Bob is reading "Spike, Mike, Slackers and Dykes: A Guided Tour Across a Decade of American Independent Cinema" by John Pierson. The book contains numerous interviews and writings by Kevin Smith.
Heather Graham auditioned for a role in this film. Reese Witherspoon had a meeting with the casting director, Kevin Smith and Scott Mosier, but both Smith and Mosier didn't enjoy the meeting and told the casting director not to bother to bring her in for an audition. Smith details this meeting in his book, "Silent Bob Speaks".
When Brody is trying to cut in line at the comic book store and is being yelled at, the "fan boy" says, "Tell 'em, Steve Dave!" The man named Steve Dave yelling at Brody is played by Bryan Johnson, and the fan boy is played by Walter Flanagan. This catchphrase was later used as the title of a podcast that Johnson and Flanagan both take part in.
Kevin Smith could not clear with the owners of "Degrassi High" to get an actual jacket logo. He took his issues with the copyright holders to the then-popular "Speaker's Corner" booth broadcast on Toronto's City-TV.
The original beginning of the movie tested poorly and was replaced by one that was filmed in L.A. The original beginning contained an incident at the Governor's Ball (the one mentioned by the TV execs).
The mall cop named La Fours is probably named after LeFors from Butch Cassidy and the Sundance Kid. In Butch Cassidy, LeFors is considered the toughest sheriff and his trademark is a white, straw hat (just like LaFours in Mallrats)
Although Renee's surname is never mentioned on screen, the cast list gives it as Mosier, a possible reference to producer Scott Mosier, but more likely a reference to Kevin Smith's ex-girlfriend, and Mosier's sister, Kristen Mosier, whom Smith noted on the DVD commentary track was the inspiration for Rene.
The scene where backstage before the game show ran by Jared Svenning (Michael Rooker) starts, Scott Mosier yelled at TS and Brodie quoting "You called down the thunder, now you got it"! That's the same line that was quoted by Kurt Russell in the Movie Tombstone (1993). Kurt Russell played character Wyatt Earp along side Rooker who played Sherman McMasters. Rooker's character was present when Russel quoted this line. Whole line is "All right, Clanton... you called down the thunder, well now you've got it! You see that? It says United States Marshal! Take a good look at him, Ike... 'cause that's how you're gonna end up! The Cowboys are finished, you understand? I see a red sash, I kill the man wearin' it! So run, you cur... RUN! Tell all the other curs the law's comin. You tell 'em I'M coming... and hell's coming with me, you hear?... Hell's coming with me!
While filming exteriors of the mall, Production Assistants would stick paper New Jersey license plates on cars in the parking lot. Occasionally, unsuspecting (Minnesota) mall customers would drive away with the prop plates still attached.
One of the main characters has a cousin Walter who is sexually odd. Brodie Bruce (Jason Lee)'s cousin Walter sticks cats up his ass. In Clerks (1994), Randal (Jeff Anderson)'s cousin Walter broke his own neck trying to give himself fellatio. This cousin Walter is the same person, ergo Brodie and Randal may be cousins.
The trivia items below may give away important plot points.
When Tricia's sex tape with Shannon is playing for the audience he asks her to first call him "Joey", and then "Donnie". This is in reference to Joey McIntyre and Donnie Wahlberg, the two most popular members from the the music group New Kids on the Block.
Silent Bob has only one line in the entire movie, consisting of: "Adventure? Excitement? A Jedi craves not these things." He had an additional line in the extended version, which was : "There was never anything good to say before."