No matter how long it's been, interviewing is still a very subjective field. It is frustrating, no doubt, to not know what you did wrong but that's what subjectivity brings.
geekam - (this question is in the wrong thread, but I can't seem to comment in the older threads, sorry) - can you tell me anything (via email) about the dentist who threatened you and the fellow yelper with a lawsuit - even just the name of the state or the size of chain of practices? I'm using gmail with address todoso253. I believe there are some dentists who do this serially.