Yea, i remember my usf interview, i had two of the nicest people ever, and everybody else say their interviews are great. However, there were only two girls there that day, and both got grilled in their interviews. In one, the interviewer started it off with "So I see you volunteered at Haiti, I don't think it's a very meaningful experience..."
I did something kinda stupid at my OSU interview too. At the end of my interview with the student, he asked me if I wanted to ask him any questions. I was browsing through the match list earlier so I figured I'd ask him a quick question about that(it was something like "what does preliminary mean?") Turns out he didn't quite know it either, so he was like "well, this question doesn't really pertain to OSU, but if you don't feel like googling it, i'll google it for you and send it to you."