Maybe...there was definitely a lack of trust there. I mean Faith didn't know anything about the Angel/Angelus situation, (Xander is such an idiot sometimes) and she just goes to his house and tries to kill him? If he had been evil, he probably would have killed her. Also, Faith did feel as if she wasn't really included in the group. It's weird, everyone liked Faith in the beginning because she seemed different, I mean she seemed like a lot of fun and then she sort of developed a "tude" and became really distant. It makes sense, it's just...interesting.