This is some excellent advice guys. And while it mostly seems pretty common sense, having it in writing like this makes it easy to put on that mental checklist. I usually think of myself as fairly poised, but I know nerves get the best of me plenty of times- especially with that self-critiquing tendency. I don't think I've ever done it in front of an AD yet, but it's probably a habit to avoid period.
Here's something: Plain ol' figure drawing/painting. Does it ever have a place in a portfolio? I noticed a lot of that from my fellow hopefuls over NYCC and didn't feel it was MY place to knock it, but to me it created the impression of unnecessary filler. No matter how pretty, there's just no content.
"The merit of originality is not novelty; it is sincerity."