So I interviewed super early at USC (September). And I generally think I'm a VERY bad interviewer. But I actually think my interview went well! We went over time, just flowing in conversation. They had to knock on the door a few times to get us out...which I thought was a good sign. And my interviewer even told me I did a "really good job". But my interviewer might have just been nice.
My other interview at another school went horribly. I was just so nervous because I knew I'd been waitlisted at USC and suspected this would be my last interview. And I got outright rejected...not even waitlisted. So I think I read that situation well. I knew I bombed.