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.
In The Dark - S1-E3
[Watching from on top of a building as Angel talks to a woman he just saved, Spike guesses what is being said.]
Spike: [as Rachel.] How can I thank you, you mysterious black-clad hunk of a night thing?
[as Angel.] No need, little lady, your tears of gratitude are enough for me. You see, I was once a badass vampire, but love and a pesky curse defanged me. Now I'm just a big, fluffy puppy with bad teeth. [Rachel reaches for Angel's head.] No, not the hair. Never the hair.
[as Rachel.] But there must be some way I can show my appreciation?
[as Angel.] No, helping those in need's my job, and working up a load of sexual tension and prancing away like a magnificent poof is truly thanks enough.
[as Rachel.] I understand. I have a nephew who is gay, so...
[as Angel.] Say no more. Evil's still afoot. And I'm almost out of that nancy-boy hair-gel I like so much. Quickly, to the Angel-mobile, away.
[Sunlight in Pylea doesn't harm vampires.]
Angel: Can everybody just notice how much fire I'm not on?
Angel: I saw their production of "Giselle" in 1890. I wept like a baby, and I was evil!
Cordelia: I finally get invited to a nice place with no mirrors and lots of curtains. Hey, you're a vampire!
Russell Winters: What? No, I'm not.
Cordelia: Are too!
Russell Winters: I don't know what you're talking about.
Cordelia: I'm from Sunnydale. We had our own Hellmouth. I think I know a vampire when... I'm... Alone with him... In his fortress-like home.
[Spike crashes to the floor and sits up looking furious.]
Spike: Right! We are gonna set some ground rules. Number one - don't hit me in the face. Number two - when I hit you in the face, you tell me how it feels, so I can write that on my clipboard. Number three [holds up the clipboard.] don't touch my clipboard.
Heartthrob - S3-E1
Wesley: It's sad. The only way some people can find a purpose in life is by becoming obsessed with demons. By the way, Gunn, technically that wasn't a Lurite, it was a Murite, a subspecies of the Lurite. The male sports a small telltale fin just behind the third shoulder.
Gunn: I'm so glad to know we're not the sad people obsessed with demons.
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.