Continuity mistake: While Nia Vardalos is talking to Richard Dreyfus, just after offering him the ice cream cone, the stains on her jacket's left lapel are either there, almost totally disappear, or change shape.
Continuity mistake: Tom receives an e-mail from Summer on day (303). At the beginning of the movie we are told that Tom and Summer met on January 8, so day 303 should be November the 6th, but the e-mail says that it was sent on May 7th, which is day 120.
Continuity mistake: When the tour bus stops at Home Depot, the position of the front wheel changes between shots. Watch the lug nuts and 5 holes around the perimeter of the rim to see how the wheel rotates even though the bus didn't move.
Continuity mistake: When penélope Cruz is sick in bed, a strand of hair appears on her forehead on the last wide angle we see of her.
Continuity mistake: When Mike and Abby are talking over a drink after his interview with Craig Ferguson, Abby's glass keeps getting more full and less full between shots.
Continuity mistake: When Walter steps into the cat poo he gets it right under the middle of the shoe. When he then lifts his foot to take a look it's stuck under the front of the shoe with no sign of poo in the middle. (00:17:30)
Continuity mistake: When Gigi calls Alex for the first time to get his opinion about a guy "Jarrad", Alex puts her on hold and goes into his office to pick up the call. In the bar the phone line is lit up where it's holding, but the office phone is not lit up at all.
Continuity mistake: When the main characters visit Montreal and with their friends they go out to eat at a diner and he creates a "home" out of 4 toothpicks, 3 sugar cubes and a coaster. As the camera goes back and forth in the conversation, watch the "home" on his plate of pancakes. It falls and appears to be scraped and turned in a different direction on his plate by the end of the conversation.
Continuity mistake: The location of Mr. Ferguson's body on the rug (while he was apparently in a "mushroom stupor") changed a few times. He started with his head near the lefthand edge of the rug, but was about a yard toward the right edge when Nick was walking past him. A little later, Mr. Ferguson's feet were at the right edge of the rug, then about a foot beyond the rug, but his body was back to the middle with the next camera shift. (01:01:35 - 01:04:23)
Continuity mistake: After Paul tells Meryl that he was hesitant about adoption during their jogging, Meryl returns home. While jogging, she was wearing very tight grey pants. At the barn, her pants are a lot looser.
Continuity mistake: During the scene when Ian is taped to the chair, the duct tape across his shoulders changes from shot to shot. Some times it touches the shoulder seams on his shirt, and other times it is several inches away.
Continuity mistake: When Pippa and Herb are having dinner, she hits the table with her fist and wine splatters on his shirt. When he stands up and walks to the bedroom the shirt is spotless.
Continuity mistake: When Joel and Dean sit at the booth to talk, Dean places two beers on the table such that the labels are facing the camera. As they talk and the camera switches back and forth between the two friends, Dean's beer switches orientation showing the label in some shots and not in others, despite the fact that he does not touch the bottle whatsoever. There isn't enough time between shots to allow him to move the bottle or drink any as the bottle remains full.
Continuity mistake: When Pierce Brosnan is first in the classroom, the writing on the blackboard keeps changing.
Continuity mistake: Mulan tricks her father into taking his medicine, and everyone has a laugh at him. Between shots she is pouring from the teapot first with the right, then the left, and one of the geezers sitting by is cackling with a different posture and hands switched as well. (00:05:10)