Once again I've run across it and feel compelled to re inscribe it. This time from Jacob Gardner on the Speaking of Animation blog.
Don't just animate "some dude". Putting a white coat on your guy just makes him "some dude" in a white coat. If he's supposed to be a Dr. at the end of his shift, he's going to pick up a clipboard with a familiarity and probably tiredness that a patient would not handle it in that way.
*he's got an update with photos