Revealing mistake: As Carrie skids into the parking spot at the start, skid marks are visible on the floor from previous takes. (00:00:30)
Road Rayge - S1-E9
Audio problem: Doug gets his license back and gets into his car. We hear the engine start, but his hands are seen on screen at the time. (00:20:00)
Road Rayge - S1-E9
Continuity mistake: When driving Doug home, look out the back window to see 2 red car lights appear instantly and out of nowhere. (00:12:20)
Road Rayge - S1-E9
Visible crew/equipment: As Doug takes Ray's keys, the film crew and equipment are reflected in the wing mirror. (00:09:50)
Road Rayge - S1-E9
Continuity mistake: When trying to get Doug to drive after the Jets' game, Ray's press pass goes from white to green instantly. (00:09:20)
Visible crew/equipment: When speaking to Doug about the book, a crew member is reflected in the window. (00:19:35)
Continuity mistake: In the first classroom scene there are two people sat to Doug's right. These people then vanish a few seconds later. (00:07:55)
Head First - S1-E6
Audio problem: Doug calls Arthur near the start and the audio is overdubbed. (00:03:15)
Visible crew/equipment: At the start when Carrie says says "it's already 20 of" look at the screen right to see the kitchen cabinets swing into place as the crew replace them. (00:00:35)
Visible crew/equipment: At the end in the theatre, a boom mic drops into shot. (00:19:00)
Head First - S1-E6
Revealing mistake: When Doug is making breakfast it's clear there is no flame coming from the gas hob. (00:08:15)
Audio problem: When Doug goes to the door to call for Uncle Hank, the audio is over dubbed. (00:04:05)
Time Share - S1-E22
Continuity mistake: When Doug Carrie and Ritchie are in the kitchen discussing how long Ritchie has to keep seeing Dorothy, Doug is making a snack involving some lettuce. The size, shape and position of this lettuce is constantly changing between subsequent shots. (00:15:20)
Continuity mistake: At the start when Arthur is ranting to Doug, the way Doug holds his coffee flask differs ever so slightly between shots. (00:07:00)
Continuity mistake: Doug comes out from the payphone and asks Carrie where did everyone go. When Carrie replies, the way she holds her glass changes between shots. (00:17:50)
Answer: Sara hasn't been mentioned in later episodes, and it suggested in later episodes that she never existed, and that Carrie is an only child. Kevin James stated that the producers couldn't think of an good plots to use with Sara, so they left her out.