She's spot on. I consider myself a competent developer (6 years experience, "big fish in a small pond"), and I don't really interview often. I've interviewed at Google twice, the first time doing 2 phone interviews and a round of on-site interviews, and the second time not making it past the phone interview.

I have prepared well for the interviews every time. I understand the algorithms, the data structures, and can program them on my own time no problem. But the second I'm in an interview setting, I lock up and can't think. I stumble across stupid thoughts (How many bits are in a byte? Oh yea, 8. But what about the 0th bit? What to do?!) and just work myself into a corner. All the while trying to seek approval from the interviewer. After about 2 minutes, I become a wreck and am hopeless.

I also don't consider myself non-social, and deal with coworkers very well. I still don't understand what it is about the technical interview setting that makes me act like this.