Character mistake: In this episode, Raymond says that after three times of proposing to Debra, she said no, and he didn't give up. However, in "The Pilot", Raymond says that the third time he proposed, she said yes.
Character mistake: When Tommy walks into the flower shop, he tells the clerk that his sister is getting married. For the purpose of their mission, Sally, the sister in question, is actually supposed to be Tommy's aunt. (00:05:20)
Character mistake: In the third instance where Superman manages to get rid of Mxyzptlk, he uses an article full of typos which spell the latter's name backwards as KLTPZYXM. Among the incorrect words is the word "citrimes", in which Superman has included an I and a T, so the correct word in context with the rest of the text should read "crimes" and thus the errors would spell KL-I-TPZYXM. Since there are no vowels in MXYZPTLK, however, what is the additional I doing here - and why didn't Mxyzptlk bother to mark it as a mistake, either?
Character mistake: The first time Arnold tries Rhonda's marriage predictor test, he says his favorite number is five, but Rhonda actually makes six moves. The second time, Arnold says it's three, but Rhonda counts off four.
Character mistake: In the flashback of Mr. Mac Fist hitting Roger in the eye, the fist hits Roger in his right eye. Once the flashback ends and goes back to the present Keenan and Kel, Keenan says "My dad couldn't see out of his left eye for 2 weeks."
The Kidney's All Right - S3-E9
Character mistake: Arthur wants to donate his kidney to Derek. It is claimed that he must be a match since he has O negative blood, but blood type is not the only thing required for a kidney donor, there are several other factors that could very well disqualify his kidney for Derek.
Character mistake: Throughout the series, General Ross refers to Gabe Jones as Gabriel. Someone of Ross' military credentials would not address another government agent by their first name. He would call him Agent Jones or simply Jones.
Character mistake: Dexter's father says he'll stunt jump over four school buses, but only three are shown.