Continuity mistake: After trying the Sgt. Salty cereal, while talking to Carrie, Doug gets out a plate to make something else to eat. After he puts the plate down on the table, the cereal box moves and switches sides. (00:13:30)
Soft Touch - S2-E22
Continuity mistake: When Doug is getting into bed while talking to Carrie about selling water filters, his grip on the duvet changes instantly. (00:10:00)
Party Favor - S2-E13
Continuity mistake: When Doug is reading his speech to Arthur, Arthur's legs are crossed or uncrossed depending on the angle. (00:09:30)
Soft Touch - S2-E22
Continuity mistake: When Doug is telling Arthur about the filters, there is a leaflet on the table. Between camera cuts, this leaflet is constantly changing position. (00:13:25)
Queasy Rider - S2-E1
Continuity mistake: When Carrie says to Doug that he can't have a bike, her hand are behind her back. Camera cuts and now her bag is on her shoulder and her hands are on her bag. (00:03:00)
Queasy Rider - S2-E1
Continuity mistake: When Arthur gets the iron, he has it down by his side. Camera cuts and now it's up in front of his chest. (00:06:30)
Queasy Rider - S2-E1
Continuity mistake: When Doug and Carrie are arguing about the smoking for the first time, the cigarette has burnt down nearly half the length in a few seconds. Cigarettes don't burn that fast. (00:12:30)
Queasy Rider - S2-E1
Continuity mistake: As Doug is telling Carrie he hates the bike, his beer and crisps vanish instantly from the sofa. (00:19:20)
Dire Strayts - S2-E8
Continuity mistake: When Doug is talking to Ray at the table, the position of his beer changes between shots. Watch the label. (00:02:45)
Dire Strayts - S2-E8
Continuity mistake: When Doug talks about grown men not being able to watch the game, the amount of head on his beer changes instantly. (00:02:40)
Queasy Rider - S2-E1
Continuity mistake: When Doug starts to explain to Carrie about getting the bike, he has his hands on the edge of the back of the chair. Camera cuts and now they have moved close together in the middle of the chair. (00:07:55)
Frozen Pop - S2-E15
Continuity mistake: When Arthur comes in and shuts Doug's window, Doug's hand goes from open to closed between shots. (00:06:00)
Frozen Pop - S2-E15
Continuity mistake: When Carrie is talking to Arthur at the start, Arthur's hands are in his lap in one shot and clasped together in the next. (00:02:45)
Continuity mistake: When Arthur tells Carrie that he has jury duty, Carrie places her used coffee mug on the counter beside the mug tree, then her used mug vanishes, the mugs hanging on the tree change, and the coffeemaker moves. (00:04:30)
Continuity mistake: The first time Doug throws a ball at the bottles, we see one bottle remain lay down on the stand. Camera cuts and this bottle has disappeared. (00:18:00)
Continuity mistake: The guy on the stall puts 3 balls down in front of Doug in a line. Doug picks up the ball furthest from the guy. Camera cuts and now Doug has the ball closest to the guy. (00:17:30)
Frozen Pop - S2-E15
Continuity mistake: When Doug goes back into the house at the start he opens the door with his right hand. Camera cuts to inside the house and now it's his left hand on the door handle. (00:01:35)
Continuity mistake: When Arthur's friend Mr. Glassman comes into the Heffernan house, a large tree can be seen on the front lawn, which we know from many other episodes there is not a large tree in front of the Heffernan house. (00:09:30)
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.