It didn't work...

William the Bloody: It didn’t work. It didn’t work. The costume. Didn’t help. Couldn’t hide. No more mind games. No more mind. Eh! Eh! Eh! No touching! Am I flesh? Am I flesh to you? Feed on flesh. My flesh. Nothing else. Not a spark. Oh. Fine. Flesh then. Sold through. Get it hard. Service the girl. (Reaches down to unzip his pants when Buffy grabs his hands and yells “No! Stop it!” and pushes him to the ground.) Right. Girl doesn’t want to be serviced. Because there’s no spark. Hey, you ain’t a soddin’ engine?
Buffy Summers: Spike, have you completely lost your mind?
William the Bloody: Well, yes. Where have you been all night?
Buffy Summers: You thought you could just come back here and be with me?
William the Bloody: First time for everything. I tried to find it, of course. The spark. The missing... the piece that fit. That make me fit because you didn’t want... Oh, I can’t. Not with you looking. (He turns away from Buffy, then gets up, walking away from her.) I dreamed of killing you. I think they were dreams. So weak. You make me weak, thinking of you. All in myself and spilling useless buckets of salt over you... ending. Angel.. he (laugh) should have warned me. Thinking that she’ll forget it, but it’s here. In me. All the time. (laugh) Spark. I wanted to give you what you deserve. And I got it. They put the spark in me and now all it does... is burn. Heh, bit worse for wear for lack of use. It’s what you wanted, right? It’s what you wanted, right? And now everybody’s in here, talking. Everything I did. Everyone I... and him. And it. The thing beneath. Beneath you. It’s here too. Everybody. They all just tell me go... go.. to hell.
Buffy Summers: Why? Why did you...
William the Bloody: Buffy, shame on you. Why does a man do what he mustn’t for her, to be hers? To be the kind of man who would never... To be a kind of man. (He begins to walk towards a rather large wooden cross.) And she shall look on him with forgiveness, and everybody will forgive and love. And he will be loved. So everything’s okay, right? (As he lays his arms and head on the cross, like a backwards crucifix.) Can we rest now? Buffy? Can we rest?

~Buffy the Vampire Slayer, Season 7