The Cautionary Tale Of Numero Cinco - S5-E6
Factual error: When the mysterious person hands Cinco the business card during the 50's flashback (in the restaurant where he is sitting waiting for business), it says "Wolfram & Hart, Attorney's at Law." Clearly, there should be no apostrophe in "Attorneys" in this context - not a mistake a professional law firm would make.
Visible crew/equipment: When Angel is fighting the demon, you can see an obvious camera and two hands in the bottom right corner. (00:27:10)
Cordelia: You want I should distract him? Make with the nice-nice while you slip by?
Angel: Don't be stupid. I'm that guy and the most beautiful woman I've ever seen is making eyes at me? It's either a bachelor party or a scam.
Cordelia: What did you just call me?
Angel: I'm sorry. You're not stupid.
Cordelia: No, after that.
Trivia: In the opening credits there is a shot of a girl standing alone on the corner of a street. This was taken from the Buffy episode "Anne", when Buffy was staying in Los Angeles.
Answer: Due to his epiphany, Angel basically had the 'true darkness' he worked so hard to reattain ripped away from him, like his soul was after sleeping with Buffy.