Revealing mistake: In the scene where Buffy is fighting the big scary lunch lady, look closely in the far away shots because you can see that the big lunch lady is now a skinny little stunt double. (00:41:55)
Continuity mistake: The time on the clock, when Buffy spots Jonathan, changes dramatically between shots.
Spike: You listen to me. [Kneels in front of her.] I've been alive a bit longer than you, and dead a lot longer than that. I've seen things you couldn't imagine, and done things I prefer you didn't. I don't exactly have a reputation for being a thinker. I follow my blood, which doesn't exactly rush in the direction of my brain. So I make a lot of mistakes, a lot of wrong bloody calls. A hundred plus years, and there's only one thing I've ever been sure of: you. [Buffy looks away; he reaches toward her face.] Hey, look at me. I'm not asking you for anything. When I say, "I love you, " it's not because I want you or because I can't have you. It has nothing to do with me. I love what you are, what you do, how you try. I've seen your kindness and your strength. I've seen the best and the worst of you. And I understand with perfect clarity exactly what you are. You're a hell of a woman. You're the one, Buffy.
Buffy: [Quietly.] I don't wanna be the one.
The Freshman - S4-E1
Trivia: At the Bronze, Buffy sees someone whom she thinks is Angel. Until his face becomes visible, revealing it's someone else, the man she sees is played by David Boreanaz.
Question: Specific answer needed, not a general "dialogue is sometimes re-recorded". Near the start of this episode, Buffy's talking to Giles about the significance of the earthquake. Buffy's dialogue sounds completely normal and recorded at the time, but all of Giles' dialogue is dubbed. I can only think he had a sore throat that day or similar, but does anyone know the specific reason he did his later?
Chosen answer: He had larangitis and because of the shooting specifications they had to have him shoot the scene with a bad throat, they then re-recorded his lines and dubbed them. At various points during the scene and indeed the episode you can see him touch his throat or rub it.