The debate teacher refers to Cher as "Cher Horowitz," but the name on her report card (viewed when her father is looking at it, after the grades have been changed) is "Cher Hamilton." The piece of mail her father tosses aside right before looking at her report card says "Melvin Hamilton" also.
When Cher is taking her driving test, she scrapes against a white car, causing her passenger mirror to be torn off. However, when the DMV proctor asks her to pull over, the mirror is still there and the car is unblemished.
In the mall scene where Tai is held over the balcony rail, when Cher and Christian get off the escalator, Cher is carrying a small purse that matches her dress. When they go to the bench to talk about Christian's black jacket, Cher puts the purse down on the bench next to her shopping bag. Later, Cher picks up her packages, but the purse is never seen again.
When Christian is first seen standing in the doorway of Cher's class room, a boy in yellow runs by and a girl in blue walks the other way. In the next shot of Christian, the boy and girl are seen again going in the same direction they were going before.
When Josh drives Cher home from the Mighty Mighty Bosstones gig, the exterior drive-by shot shows an earlier one which was recycled (the one when Elton offered to drive Cher home from the party). Note that the car shown was Elton's Camaro rather than Josh's Honda. In addition, the interiors of the car during that scene are in fact that of a Camaro (compare to the earlier scene in Elton's car), not of Josh's Honda.
When it cuts to the wedding scene implying the bride and groom are Cher and Josh, the groom (shown from behind) has a full head of hair. When the camera shows a zoom shot of the couple, the groom is now bald.
As Cher makes her appearance in the white dress and descends the staircase greeting Christian along the way, Josh is baffled by her appearance and watches in awe, as she makes her entrance. However, from Josh's view and the angle of his head, he would actually be looking toward the front door and foyer as there is a huge wall blocking almost the entire view of the staircase except the last few steps.
When Cher and Josh are sitting at the top of the stairs in the wide angle shot Cher brushes her hair back, but it remains a little messy. The very next shot, a closeup, has her hair perfectly parted over her shoulder.
In the scene where Cher is "negotiating" with her teacher (Mr Hall) to get her grade raised, which he'll have no part of, he escorts her to and out the classroom door. The door is swung open out into the hallway, and he pulls it closed. In the next scene Cher is in the hallway with her back against the now closed door, but there are no hinges to her left. They would have to be there if the door opened outward from the classroom to the hall. This door opens inward.
When Cher and Tai are at the party with Josh, Tai ties her sweater around her waist, yet, each time the camera reverts back to Tai, throughout the scene, you can see the sweater being put back on and taken off about 2 or 3 times.
When Cher and Josh are on the couch talking while she is putting clips in her hair, a shot from behind shows Cher putting a small claw clip holding most of her hair behind her head. She is in the middle of doing this when the shot changes and she is suddenly putting a small clip on the right side of her head and the claw is already in place.
When Cher and Donnie are first walking through their school, six extras wearing white overalls and black shorts walking towards them are nowhere to be seen after the camera focuses back on Cher and Donnie.
When Cher is giving her speech how Physical Education in her school is a disgrace, behind her an extra is seen walking behind the fence, after the shot of the girls cheering and the camera cuts back to Cher about 2 seconds later the Extra has disappeared.
When Cher and Dionne are driving to school, at one point the shadows of the crew, the camera rig truck, and boom microphones can be seen on the hedge behind Dionne. Once the Jeep turns the corner and Dionne lectures Cher on the importance of Stop signs, the shadow is no longer visible.
When Cher is describing her efforts to get her grade changed in PE from a C to a B (10:00), the camera pans past some cheerleaders. The second to last cheerleader's skirt is caught on her pom-pom, fully revealing her pink panties. Knowing the movie,it may have been intentional.
The day after Tai got her make-over and needs a boyfriend, Cher says that Elton is recently single. Tai then asks who Elton is, when on her first day of school, Cher specifically pointed out who he was. However, she easily could have forgotten his name. Many people take time to learn the names of people they just met.
Near the end of the film, Cher gets upset after flunking her drivers test & storms out. She walks along until she sees a clothing store, and purchases clothing. But she clearly left the house with no purse & wearing a mini dress. How did she pay for the clothes?
When Summer is carrying the snowman out of the party to her car and is holding it, you can see the extension cord that the snowman is plugged into, but it's still lit when she shuts the door and the cord is hanging out the window. It is also still lit when she drives off.
When Mel and Josh are sitting at the dining room table working on documents for Mel's case, Cher comes down the stairs in her white dress. She is first seen at the top of the stairs, then the camera switches to Josh, who apparently is watching her walk down the entire flight of stairs. However, from where Josh is sitting, he can only see the bottom few steps and could not watch her descend the entire staircase.
When Cher & Josh bring home the takeout for her father and his lawyers, we see a cardboard carton with 4 full containers of coffee on the table. Someone lifts the carton up and the cups tip, revealing the cups to be empty.
In gym class, when Dionne and Cher first meet Tai, they inform her that the school does not serve tea. However, when Tai is in the cafeteria conversing with Travis, you are able to view tea directly behind Travis.