Continuity mistake: Benson visits Stabler at his home to confronts him about the FBI detail he has ordered to protect her. They talk outside and then Benson is seen walking away. The next shot shows a side shot of Benson approaching him again in silence but mouthing words to him. (00:49:00)
Visible crew/equipment: When Angel is fighting the demon, you can see an obvious camera and two hands in the bottom right corner. (00:27:10)
Factual error: The Lockheed 1011 was only produced until 1984. There's no way that in 1999 Toby would be flying on one that "just came off the line 20 months ago."
Continuity mistake: Tony's hair length alternates between a short buzz cut and longer in different shots in the scene where Sil, Paulie and Chris visit him after his mother dies.
Continuity mistake: Did any one else notice that Sheridan gave birth without ever taking off her pants?
Plot hole: In the episode "10,000 Steps," the parents from Amy's case say they adopted their first son Daniel when he was 3 because they thought they couldn't have biological children. Howeve,r the birth of their other son Seth proved that theory wrong. But Daniel is 13 and Seth is 12, so when Daniel was 3, Seth would have been 2 already.
Revealing mistake: At the end it is not Helen against the filing cabinet - the face is different. Obviously a body double.
Character mistake: In the final episode, Carlos visits Doc in the psychiatric hospital for advice concerning his upcoming marriage to Holly. While talking, Carlos refers to Doc's deceased wife as "Linda", while throughout the series, it has been made very clear that her name was Deborah.
Plot hole: In each episode, Emmy, and Max travel to dragon land (often for a long time) without their parents ever knowing. This makes no sense. Their parents would notice sooner, or later that Max, and Emmy always go in, and out of the house, or that it's always quiet in Emmy, and Max's playroom. You'd think Emmy, and Max's parents would get suspicious, and would question their children accordingly.
Continuity mistake: Emma falls off the roof and into a water butt when she is being chased by the villains, the police pull her out and she is soaking wet. A few seconds later she screams when the villain catches Nicola, and when they fall through the roof she is dry.