Spike: I don’t understand. This sort of thing’s never happened to me before.
Willow: Maybe you were nervous.
Spike: I felt all right when I started. Let’s try again.
*leaps towards her only to draw back immediately; tries again, same result* Ow! Oh! Ow! Damn it!
*gets up, kicks the dresser and paces around the room*Willow: Maybe you’re trying too hard. Doesn’t this happen to every vampire?
Spike: Not to me, it doesn’t!
Willow: It’s me, isn’t it?
Spike: What are you talking about?
Willow: Well, you came looking for Buffy, then settled. I—I… You didn’t want to bite me. I just happened to be around.
Spike: Piffle!
Willow: I know I’m not the kind of girl vamps like to sink their teeth into. It’s always like, “ooh, you’re like a sister to me,” or, “oh, you’re such a good friend.”
Spike: Don’t be ridiculous. I’d bite you in a heartbeat.
Willow: Really?
Spike:
*sits on Willow's bed* Thought about it.
Willow: When?
Spike: Remember last year, you had on that… Fuzzy pink number with the lilac underneath?
Willow: I never would have guessed. You played the blood-lust kinda cool.
Spike: Mmm. I hate being obvious. All fang-y and “rrrr!” Takes the mystery out.
I loved this scene. Both because of how calm and relaxed Willow is as she's talking about Spike's sudden problem of being unable to bite... and the slow birth of friendship between the two. You really get to see into Spike's character. He loves to have the "bad boy" look... but he doesn't always like acting the part.
Anyway... if I encountered Spike during this occasion, I probably would be as calm and collected as Willow is too. *laughs*