If June's name was mentioned her mother's tone was approving, and if Connie's name was mentioned it was disapproving. This did not really mean she disliked Connie, and actually Connie thought that her mother preferred her to June just because she was prettier, but the two of them kept up a pretense of exasperation, a sense that they were tugging and struggling over something of little value to either of them. Sometimes, over coffee, they were almost friends, but something would come up—some vexation that was like a fly buzzing suddenly around their heads—and their faces went hard with contempt.
This passage really stuck out to me because of how Connie differentiates herself from June and her mother. The air of teenage superiority that Connie projects is vastly different from the disorientation she develops by the end. She likes to believe that she is different from everyone and isolates herself in an egotistical jail. Arnold Friend does the same when he goads her to leave her house and to escape with him, as her "lover". The delusional thinking of both of them is very transparent yet is strong enough to guide them to their demise.