Revealing mistake: Look at Harry and Sally carrying the Christmas tree together. Then jump towards the end of the movie when Sally is dragging on her own a tree for the next holidays. Each garland and even the fake snow covers on the sills are the exact same one year later, down to each crease. At least the vendor changed jackets. (00:48:35 - 01:21:50)
Continuity mistake: Once Harry met his ex and her current partner, Sally in the view from behind moves her arm behind his - the movement can be easily spotted because of the lyrics sheet she is holding. But in the next shot, she asks him if he's OK, and a few seconds later, she is repeating that same movement. (00:59:15)
Continuity mistake: Harry is blowing off some steam with his friend, practicing swings. When he says, "Why can't you give me credit for this?" look at Bruno Kirby; his baseball bat switches hands, but he is still holding it with both hands and repeats the movement in the next shot. (00:43:35)
Other mistake: Sally phones Harry while he is staring at a dipping bird. She tells him that Casablanca is on TV, and he specifically asks for the channel. "Channel 11," she says. When she says "Last scene" later, you can see on the display of Harry's TV set that he's tuned to channel 07. (00:35:30 - 00:37:40)
Factual error: Marie spots Harry poorly hidden in the "personal growth" section of the bookstore. The scene is supposed to take place in 1987, but there are books both next to him ("Sex and Morality; Who Is Teaching Our Sex Standards") and to the girls ("Making Life Right When It Feels All Wrong") that were published mid-1988 and couldn't be there. (00:29:25)
Continuity mistake: When Marie is going through potential available dates to pitch to Sally, look at Carrie Fisher's wrist, in particular when she mentions the second name, "Ken Darman"; the hands of her watch point to a different time practically every shot. (00:24:55)
Continuity mistake: Over lunch, Sally tells her two friends that she broke up with Joe. Meg Ryan's hair is conspicuously in front of her shoulders in the close-up but behind her shoulders in the wider angle. (00:23:50)
Continuity mistake: On the plane, the guy sitting next to Sally decides to be a bro to Harry hitting on her and switches places. A stewardess behind them vanishes in thin air as the shot changes. The two stewardesses keep disappearing / changing position throughout the scene. (00:18:15)
Continuity mistake: During the conversation between Joe and Harry, Meg Ryan's head position is inconsistent between angles, sometimes just for a subtle tilt, other times more conspicuously. For instance, when the two guys are entertaining awkward laughter before Joe introduces Sally to Harry, she looks in opposite directions. (00:15:25)
Continuity mistake: Sally is making out with Joe (Steven Ford) at the airport when she spots Harry staring at them. She taps Joe on the arm; in the next camera angle, her left hand is on his lapel, but it was nowhere to be seen earlier. (00:15:20)
Continuity mistake: At the beginning of the airport scene, watch out for the moment when Billy Crystal first walks by. Two blonde flight attendants are carrying their bags. Focus then on the black woman in a patterned dress that gets in frame from the left side. As soon as the camera angle changes, the same woman is seated, slightly out of focus behind Meg Ryan and Steven Ford. (00:15:20)
Factual error: The movie begins in 1977, as stated, and initially shows Harry and Sally getting to New York. They drive by the Washington Square Arch. Through the arch, you can see in the distance the iconic silhouette of the Twin Towers, one of which sports the characteristic large antenna, which was added two years later, in 1979. (00:13:15)
Continuity mistake: In the second part of the diner scene during Harry and Sally's drive from Chicago to New York, the waitress in pink appears at opposite ends of the diner in close-ups behind both Meg Ryan and Billy Crystal, while a staff member in white carries a bowl from right to left behind Meg Ryan at least three times. (00:10:20)
Continuity mistake: In the 1977 diner scene, as Meg Ryan calculates how to split the bill, the keys on the table face opposite directions depending on the camera angle. (00:10:15)
Continuity mistake: During the first scene showing Sally Albright's peculiar way of ordering food (Rob Reiner notes in the DVD commentary that it was modelled directly on Nora Ephron's real-life behaviour), the water levels in Sally's and Harry's glasses change repeatedly between shots. (00:09:10)
Answer: Sally could be upset for having to drive Amanda's boyfriend, or it could be awkward because they don't know how to say goodbye. There could be a number of reasons why things appear tense between Sally and Amanda, just not explained.
That was a big question mark for me as well when I watched the movie, to the point that I had to re-watch the beginning because I was sure I had missed something; their behaviour doesn't make sense.
Sammo ★