Angels and Potentials, maggots and guilt.
Buffy can go screw herself. Or better yet, go screw her vampire boy-toy. Fucking bitch. She has no idea. Who the fuck does she think she is, saying that about Chloe? She always looked up to you, relied on you. Because you were her sister. Step, sure, but it may as well have been blood. She had been there for you when you found out about vampires and being a potential with no idea that she was, too. She comforted you when your first girlfriend dumped you, sneaking extra-cheese pizza into the house, even though her mother was a nut who didn't allow anything that wasn't no-cal. She held your hand while they gave you 20 stitches in your eyebrow after a nasty fight, and she was always the one who saw the bright side of anything.
And then you told her that no one could know you were sisters, and you let her believe it was because you were ashamed of her when really you wanted to distance her from you so it wouldn't hurt her so badly if you died.
She wasn't an idiot. She was just a younger sister who thought no one loved her. And you let her believe it.