Revealing mistake: When Doug and Carrie are waiting in line at the DMV, a man (casting extra) can be seen just outside the doorway waiting to enter the scene. When the shot changes and Doug and Carrie approach the counter, the man casually enters the set. (00:03:30 - 00:04:00)
Continuity mistake: When Doug is putting lipstick on Carrie, the way she is holding her arms changes between shots (crossed then uncrossed). (00:14:50 - 00:15:40)
Visible crew/equipment: Throughout this episode you can see stage lights reflecting off Carrie's glasses - most notably in the bedroom when Doug finally convinces her to join the party. She looks toward the camera and a series of stage lights are reflected very evidently. (00:16:25)
Continuity mistake: When Carrie takes Doug into the back yard to yell at him, after she is done swinging at him, she puts her hand up to her chin. First it's her left, then right. It changes between shots. Each time the camera goes back to her it happens.
Other mistake: At the end when Doug takes the bandages off Carrie's face, the bandages come off far too easily as if they weren't really attached in the first place.
Mean Streak - S4-E3
Continuity mistake: When sat at the table at the start, the bottle top keeps changing position in relation to the edge of the table. (00:03:00)
Mean Streak - S4-E3
Visible crew/equipment: After giving an interview Doug walks over to Deacon and a tape marker from earlier in the scene is visible on the floor. (00:05:20)
Mean Streak - S4-E3
Continuity mistake: When Doug is talking O'Boyle about the old guys, the time on the clock goes back. (00:05:30)
Mean Streak - S4-E3
Visible crew/equipment: Doug is debating smashing the woman's parcel. As she opens her door a black tape marker is visible on the floor. (00:15:50)
Continuity mistake: When Doug says he was reaching for a fig newton, the way Carrie is stood changes between shots. Note her right arm. (00:04:50)
Continuity mistake: When Doug, Carrie, Deacon and Kelly are looking at the damage caused by the accident, the same kid in the black and red hat checking his watch walks by twice. (00:05:10)
Continuity mistake: At the accident scene when Deacon asks to have a picture taken with him and Doug, the same couple walks by three times. (00:05:30)
Continuity mistake: When Spence and Kirby are talking about why Spence can't make him a PB&J sandwich, the way Kirby holds the red action figure keeps changing. (00:06:15 - 00:06:55)
Continuity mistake: When Doug, Carrie, Deacon and Kelly are at Coopers, the man in the blue shirt who is talking to the women sitting at the table behind them appears, disappears, walks off and then reappears again during this scene. (00:08:20 - 00:10:40)
Continuity mistake: When Doug, Carrie, Deacon and Kelly are at Coopers talking about the auto-repair bill, Carrie's menu instantly switches from on the table to in her lap and then continues to switch depending on the shot. (00:08:30 - 00:09:10)
Continuity mistake: When looking at the quote for the repair bill, its position on the table in relation to Kelly's menu is constantly changing. (00:08:40)
Continuity mistake: The way Carrie is standing and holding the banana and pop-tart changes as Doug admits that he was trying to look into the strip club, not reaching for a Fig Newton. (00:15:15)
Continuity mistake: When Deacon is asking Doug if "Chain of causation" is a legal term, him arm goes from straight to bent between shots. (00:17:20)
Continuity mistake: After Spence and Kirby's arm wrestle, the way Spence holds the action figure keeps changing between shots. (00:51:10 - 00:51:55)
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.