When Riley runs away from home she leaves in the morning and begins walking to the bus stop. When her parents arrive home that night to find her missing she is still walking to the bus stop, approximately 6 hours later.
Right at the beginning of the movie when baby Riley appears, her mother appears to be wearing glasses. When the mother is visible from Riley's point of view, the mother has no glasses.
When Joy and Bing Bong are trapped in the disposal, Joy takes the memory of the team celebrating Riley from the ground, even though it should be in her bag and was never taken out of it in this context.
In the Swedish version Riley's name is Jenny. When at Dream Productions they try to give "Jenny" a nightmare, the director says that they're trying to wake her up. However, in the Swedish version, the director says that "they're trying to wake Riley up", instead of Jenny.
In the opening scene, the newborn Riley sees her parents in full-color. Human infants are born colorblind. The eyes' rods and cones (ergo, the ability to see color) don't fully form until infants are about about 3 months old, assuming they're going to have trichromatic color vision.
During dream production, when Riley is dreaming that her teeth are falling out, a production worker is dropping "teeth" in front of the camera. Since the camera is supposed to show Riley's point of view the falling teeth shouldn't be seen by the camera.
Sadness's glasses have no earpieces, yet stay on throughout the film. Given that everything about the character design of the emotions is stylized, there's nothing wrong with this.
When Riley and her mother discover that San Francisco has one type of pizza, Anger states that both Hawaii and San Francisco have ruined pizza, whereas, in fact, it was Canada that invented the Hawaiian pizza. There is a possibility that Riley did not know this fact.
In the UK release of the film, Riley's father daydreams about football (soccer) instead of ice hockey. However, given that Riley still plays hockey in that version, there was no real need for the change, especially as in a film set in the US it would be more usual to daydream about a predominantly American sport.
While it makes for a humorous moment, there is no way Riley (and her emotions) wouldn't have known about the big move from Minnesota far earlier than depicted. She would have known long before that she would be moving to a new home, new school, new hockey team, etc. so the idea that she and her emotions are caught completely off guard are is far-fetched.