Its basically a few areas on the casing:
Left portion of laptop when open near speaker grill is ever so slightly un even with plastic piece. (found by running my hand along it)
Bottom right portion of laptop is tiny bit raised off of desk when open. Noticed this...don't remember how....I think I was admiring it.
Back henge on the left and right sides don't seem to exactly line up with screen, but then again this "imperfection" is semetrical and leaves me to believe its not a manufacturing flaw, its just as-is.
Incredibly picky? Yes. But when building models, or hand drafting, or doing anything for school (Architecture) I'm a perfectionist, and so I notice EVERYTHING
which is a blessing and a curse. And I just love admiring Apple's design.