Inside Out - S4-E17
Angel: All this time, it was you, wasn't it?
Cordelia: Took you long enough to figure it out. But nice turn with the Lorne bait. You know, there was a time I would have seen that one coming eons before it ever crossed your tiny little mind.
Angel: Because you're so clever.
Cordelia: On a scale of you to me? Pretty damn.
Gunn: As evil blood-sucking vampires go, how would you rate Angelus?
Wesley: Historically, as bad as they come. Especially when he was with his sire, Darla.
Cordelia: We're researching her now to see if she has some kind of resurrection powers. Maybe she's a vampire cat with nine lives, or something!
Gunn: So he and Darla together, bad combo?
Wesley: They rampaged through half the known world until Angel got his soul.
Cordelia: Imagine Bonnie and Clyde if they had 150 years to get it right.
Angel: Can I come in?
Kate Lockley: Oh, that's right. You need to be invited in, don't you?
Angel: You've been doing your homework.
Kate Lockley: Want to quiz me? I'm just full of fun facts. For instance, I learned your friend has been in L.A. Before. Did you know that? Yeah, at least twice. Once in 1929 and again in 1963. Oh, and there was something in Boston in 1908. I think he was there, too.
Angel: So you believe me.
Kate Lockley: Yes, I believe you.
Angel: Good, because he's planning something else.
Kate Lockley: Angelus. Isn't that what he called you? Angelus. I looked it up, it's all right there. The demon with the face of an angel. A particularly brutal bastard by all accounts. Oh, and no, you can't come in.
Illyria: [after killing a guard and tossing the body aside.] Your race is weak. How did you get to control all this?
Knox: Opposable thumbs?
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.