Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: In the beginning when the Scooby gang and Giles are talking in the cafeteria and Giles asks Xander to help him, in the first shot Xander doesn't have his hand on his drink, but when the shot cuts to the opposite angle, suddenly he has his right hand grasping the dop of his drink.
Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: When Buffy is checking out the locker room after the credits, she starts to close one of the lockers. It cuts to the opposite angle and the locker is All The Way open, and she starts to close it a second time. The way she's holding the locker door also changes instantly between edits.
Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: In the beginning of the episode, when Cordelia's date is in the locker room and he talks to two other students, pay attention. There's a combination lock and a baseball bat on top of the lockers. They change positions repeatedly between cuts, getting closer and further apart almost at random depending on the shot.
Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: When the school-bell rings at the beginning of the episode after Cordelia talks about hitting the girl on the bike, in the first shot Willow is just starting to put her book into her backpack and is still seated. In the next shot, Willow is suddenly starting to stand up and has already put her book away.
Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: When Cordelia is talking about hitting the girl on a bike with her car and the bell rings, pay attention to Willow's hands. As it cuts from the front angle to the back angle, Willow's hands instantly change positions. (In the first shot, her hands are together, but in the next, her arms are crossed in different directions).
Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: When Cordelia raises her hand in the class at the beginning of the episode, look at Harmony's hand on the desk next to her. Harmony's hand instantly changes position and moves about six inches to her left between cuts when Cordelia is called on.
Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: This is subtle and hard to notice. When the teacher is giving a lecture in the beginning, she says "Ok, so talk to me people " and starts to turn and walk to her right. When the camera cuts, she starts to turn and walk to her right a second time. It goes by fast, so it's kinda hard to see.
Nightmares - S1-E10
Audio problem: When the Scooby gang goes back to the hospital to try to wake up Billy, they talk to the doctor, who mutters "My hands." However, his words don't match his lip movements in the slightest. He seems to be muttering something else entirely.
Nightmares - S1-E10
Continuity mistake: When Xander, Willow and Giles go out front after Xander punches out the clown, when it changes angles as Willow says "What do we do?!", Xander goes from facing away from to facing towards Giles instantly between cuts.
Nightmares - S1-E10
Continuity mistake: During her "duet", at one point, Willow goes from facing the crowd to facing the other singer instantly between cuts.
Nightmares - S1-E10
Continuity mistake: When Willow is pushed onto the stage, the other singer goes from facing her and gesturing towards her with his hand, to facing forward with his hand down by his side instantly between cuts.
Nightmares - S1-E10
Continuity mistake: When the Scooby gang splits up and Xander walks into the decrepit hallway with debris on the floor and swastikas painted on the walls, he closes the door behind him, but a few shots later, it's suddenly wide open again.
Nightmares - S1-E10
Continuity mistake: When Buffy is confronted by the monster in the school gym, after Billy flees, the monster hits Buffy, and she falls on her back, and her legs both fly up in the air. It cuts to another angle, and her legs are no longer in the air.
Nightmares - S1-E10
Continuity mistake: When Buffy is taking the test in history class, in a wideshot, her teacher walks past her and his shadow passes over her as he walks by. It then cuts to a closeup, and we see his shadow quickly pass over her a second time.
Nightmares - S1-E10
Continuity mistake: When Buffy goes to take her history test near the beginning of the episode and is talking to Cordelia outside the door about how she doesn't think she can pass, pay attention. As it cuts back and forth from Buffy to Cordelia, you see the same student (an African American girl with a black jacket, white shirt and earrings) enter the history classroom twice.
Nightmares - S1-E10
Continuity mistake: At the beginning, when Joyce drops off Buffy at school, pay attention to the car windows. They open and close repeatedly throughout the scene depending on the angle. (This seems to be for the benefit of the scene depending on the camera angle. They seem to lower the window the camera is shooting through while closing the one on the opposite side, and it switches back and forth. Still, it's a mistake).
Nightmares - S1-E10
Continuity mistake: At the beginning, when Joyce drops off Buffy at school, Joyce lets go of the steering wheel and lowers her arms. It then cuts to the opposite angle and Joyce is suddenly holding the steering wheel again.
Nightmares - S1-E10
Continuity mistake: At the beginning of the episode, when we first see Cordelia, she's looking in a hand-mirror and makes a snotty remark to another student. Instantly between the second and third shots she goes from holding the mirror with hand to both hands.
Nightmares - S1-E10
Continuity mistake: At the beginning of the episode when Buffy and Willow stop at Buffy's locker, in the first shot, Willow has her backpack strap on her shoulder and takes it off. It then cuts to another angle and Willow's backpack strap is back on her shoulder, and she takes it off a second time.
Nightmares - S1-E10
Continuity mistake: In the beginning dream sequence, when Buffy is surprised by the Master and backs up into the wall, watch her two pigtails. As the scene cuts back and forth between Buffy and the Master, her pigtails move from behind her shoulders to in front of her shoulders and back several times. First they're both behind her shoulders, then only one is behind, then both are in front, then one moves back behind again, etc. Obviously multiple different takes were cut together in editing.
Chosen answer: Angel is saying that he is still jealous and Buffy recognizes that this is his way of saying he wishes that they could be together. That is why they both smile.