John goes to the dance club with his son Evan. As the camera enters the club, John's son Evan and his girlfriend are dancing in the crowd. In the next shot, they are sitting with John just getting ready to go out onto the dance floor.
The size of the Detective's apple pie when Beverly first goes to see him changes between shots.
When Bobbi and the boys first go to the diner, Bobbi takes off her ponytail and then clamps it back on. When she clamps it, the top is smooth, but in the next shot there is a clump of hair standing up that goes in and out of the frame. In the very next shot it's smooth again.
When John searches for ballroom dancing websites online, the search box says "ballroom dance" but when the search screen comes up, it reads "search results for ballroom dancing"
When John and Miss Mitzi are dancing at Dr. Dance, they bump into Link and his dance partner. The dance partner has her hair covering her ear (down) in the wide shot, but in the closer shot, her hair is behind her ears.
In the first ballroom lesson Miss Mizzie teaches standard slow waltz mirror-inverted: she teaches "left foot forward, right foot side, right close..." which are ladies 2nd part steps. Men's are "right foot forward, left foot side, right close".
When Richard Gere's character is at home washing his SUV, the car is covered in soap suds but the driver's window is wide open.
A major plot point is John's realization during the dance competition that his wife and daughter are in the audience, meaning they have discovered his secret. However, the idea that Bobbie would hear someone in the crowd yelling "Go, Dad!" over the music and would assume it was John's daughter is preposterous. Even more preposterous is the suggestion that a couple in a dance competition would break their concentration to have such a frivolous conversation.
When John Clark first sits down at Miss Mitzi's Dance School, the boom mic's shadow falls on Vern's face.