Deliberate mistake: Lindsay is not at Caleb's funeral in the last episode of season 2, "The Dearly Beloved". It's unlikely that she would have missed it - she is still on good terms with him and he is her father, the only reason she left was to be with her mother, not because she didn't love Caleb.Obviously they didn't want to create another drama with having Lindsay there while they had to focus on the important story-lines - Caleb's death, Kirsten's drinking and Marissa shooting Trey.
Continuity mistake: When Ryan is lighting Marissa's cigarette with his, at the start of the shot it's full, then the shot goes to Ryan and it's still full. But then the shot goes to Marissa and if you look at Ryan's cigarette you can see it is almost all gone. Then the shot goes to Ryan and the cigarette is full again. (00:09:00)
Kirsten: Is everything okay?
Seth: Hmm? Yeah, it's fine.
Theresa: I'm pregnant.
Seth: Well, except for that.
Trivia: Mischa Barton also played the dead girl who threw up in The Sixth Sense.
Question: When Ryan goes to Marissa and Alex's apartment (after Alex told him to stay away from Marissa), he says, "If you have to work this hard, it isn't working." What does he mean?
Answer: He means that if Alex has to go so far as to forbid Ryan from seeing Marissa in order to maintain her relationship with her, their relationship obviously isn't working.