Line callbacks: Which are intentional? Important?

[iigreenii]

I'm nothing was a line used in both Angel and Buffy.

Spike said it in Seeing Red.

Spike: "You know, everything always used to be so clear. Slayer. Vampire. Vampire kills Slayer, sucks her dry, picks his teeth with her bones. It's always been that way. I've tasted the life of two Slayers. But with Buffy...It isn't supposed to be this way. It's the chip. Steel and wires and silicon. It won't let me be a monster. And I can't be a man. I'm nothing."

The character Judy said it in Are You Now or Have You Ever Been.

Angel: "Why'd they fire you?"
Judy: "Because I'm not what I say I am. I've been passing since I was 15 years old."
Angel: "Passing?"
Judy nods: "For white. My mother was colored, my father - I didn't even know him! My blood isn't pure. - It's tainted."
Angel: "It's just blood - Judy. - It-it's all just blood."
Judy: "Nobody believes that! Not even my mother's family. I'm not one thing or the other. I'm nothing."

It could have been more than 2 times someone said they were nothing. These are the only two I remember now. Both were similar situations.

EDIT:I believe Dawn said it too in a episode. I'm not sure.

[Miss. Rogueh]

I think the "I'm nothing." line is because everyone feels like that at some point, and with a universe so vast it is normal to feel like that. I think that one is more help fans connect with the charactors than anything else.

[iigreenii]

I just thought of another line that was repeated. You're a hell of a woman was told to Buffy by Riley in As You Were and Spike in Touched. I don't know if this line was intentional or not.