"Misery loves company. And I like knowing that a person can get as calloused as you and still feel things. You know, instead of just being...stone."

She wasn't being fair. Buffy could handle being cruel, but she didn't care to be unjust. So: "Don't get me wrong. I'm not glad you're unhappy about something. Just...relieved that I could get as far gone as you and still have an emotion or two to indulge."