In order for Jeff Daniels to attain Harry's frizzy hair, during filming he was instructed to wash his hair only, and not to use conditioner, blow dry it, or even comb it.
The restaurant scene (with Seabass) was filmed in Ft. Morgan, Colorado. However filmmakers originally wanted to film this scene at a restaurant in Wiggins (about 15 miles west of Ft. Morgan) but after viewing the script the owner refused.
When Harry and Lloyd are in the car, Lloyd asks if Harry wants to hear the most annoying sound in the world. This was not originally in the script (you can tell by the look on Jeff Daniels' face).
In the scene where Harry and Lloyd are escaping the "gas man", when they are running out to the dog van, there is a guy in the background urinating against a wall.
In the bar scene in Aspen, the line "No way... that's great. We've landed on the moon!" was not in the script but made up by Jim Carrey on the spot during shooting.
Among the many writings on the gas station bathroom stall are: "Why are you looking up here when the joke is in your hand?", "Bye Bye William Frawley", "NAMBLA Rules", and "Why the hell is everyone so goddamned angry?".
The sports car Harry and Lloyd purchase is a Lamborghini Diablo. Supplied courtesy of Emich Lamborghini, Golden, Colorado - which has since closed down.
During the men's room stall scene, when Lloyd checks the time, the close-up of his wristwatch reveals it to be a "Casino Alarm Chronograph", suggesting it is a fake of the already, very inexpensive brand, Casio; it also lacks any of the dials found on a real chronographic timepiece, along with the 5, 6, and 7.
Jim Carrey was initially offered $700,000 to appear in the film. However, the offer went in the same week when Ace Ventura: Pet Detective opened at number 1 in the US box office, so by the time Carrey's agents had renegotiated with the film's producers, his salary had upped itself to $7 million, almost half the film's budget.
When the film went to the top of the US box office, it gave Jim Carrey the distinction of being the first actor to have three films go straight to number one in one year (those films being this, The Mask, and Ace Ventura: Pet Detective).
This is the second movie released in the same year in which Karen Duffy plays a character named Shay. She also played a character named Shay Stanley in Blank Cheque. It was also the second movie released in the same year in which Jeff Daniels played a character named Harry. He also played Det. Harry Temple in Speed.
Bennett Yellin's initial draft of the script was apparently so disjointed that it had gained a negative reputation among film investors. After the script was re-written, it was pitched to producers under the fake title "A Power Tool Is Not a Toy", in order to get them to even read it.
The bikini girl played by Anna Anka is speaking Swedish in the bikini bus scene. She greets with "Hej allihopa" (Hey everybody) and says goodbye with "Hejdå" (Bye).
An alternate ending scene was filmed where Barney the bellman offers Harry and Lloyd the job of babysitting his grandson, who turns out to be the blind boy to whom Lloyd had sold his dead parakeet.
An entire subplot was filmed involving Mary's kidnapped husband Bobby being kept in a wooden shipping crate, but was ultimately discarded. The brief scene where Nicholas and Shay discuss the snow owl incident had originally led into a scene where Bobby manages to escape while still inside the crate.