Cordelia wanted to part of this group, wanted to have real friends. She'd been popular all of her life and couldn't remember ever not having people following her around, hanging on every word she said, and she had called them friends. But they weren't her friends, not really.
She realized now that that Harmony and the others didn't know what truly being friends meant, until now she hadn't either. She couldn't count on them for anything other than to agree with her about boys or the latest fashions, or who to mock. Willow had talked to Xander on the phone all night because his parents were fighting and he wanted to block out the sound. Willow hadn't complained or even acknowledged that he had woke her up or that she needed her sleep, she had just talked to him. All the people that had followed Cordelia around most of her life, and she couldn't name a single person who she'd even confide something like that to, and certainly not someone who would stay up all night for her.
She regretted how she had treated them for so long, not because she suddenly had a lot in common with Willow or Buffy. But because now her life had changed so drastically and she desperately needed someone she could talk to, someone who wouldn't care that she could no longer afford the clothes, cars, and jewelry she used to have, someone who would stay up all night just to listen to her talk about her fears. They didn't see that she was alone and needed support now because she hadn't bothered to see beyond the surface in the past. She was alone now, and it was her fault.