Dumb and Dumber (1994) - 75 mistakes
Directed by Peter Farrelly, starring Jeff Daniels, Jim Carrey, Lauren Holly
Continuity: In the scene where Lloyd drops Mary off at the airport and hugs her goodbye, in the background there are two men walking towards them. The camera changes to the angle behind Mary then behind Lloyd and then back to the side. When it returns to the side view the two men are farther away but still walking toward them.
Continuity: In the scene where Harry and Mary go out on the date to the ski resort, when they get into a snowball fight, the camera shows Harry, and it's snowing, but when they show Mary (who is supposed to be right beside him) it is not snowing. It keeps doing that, when it shows Harry it's snowing, and Mary it is not (or vice versa).
Continuity: After leaving the diner, Lloyd & Harry are pulled over by a motorcyle cop (Harland Williams). As the cop notices the beer bottles on the floor of the van, you'll notice his hair has a curl hanging over his forehead. Right before he takes a drink of one of the bottles, the curl is gone. It cuts to Lloyd & Harry trying for a brief second , and when it cuts back to the cop saying "You'd shut your mouth if you knew what was good for ya," the curl is back.
Continuity: When Harry and Lloyd go to the preservation dinner, Nicholas is standing by the front door. A few minutes later, he is up on the stage starting the presentation and introducing Mr. Swanson. Then instantly, he is back by the front door talking to his comrade. There is no way Nicholas could have done what he did in so little time - he doesn't look out of breath -- and without being seen.