"them"

You know who they are and you know you're annoyed by them too. If you ARE one of them, stop. You've rolled your eyes at them, perhaps you've been caught making a face. Natural habitat: front and center. Temperment: over anxious. Communication habits: Mm-hmm, mm-hmm. Favorite exercise: hand-raising.
The 'over-nodders,' as I so fondly call them, exist in almost every type of class and appear to increase in numbers as we move up the chain from high school to graduate school. They tend to congregate in classes with a cultural subject matter: namely literature and art. Oh dear God, the art class nodders. Perhaps the most offensive of the species. Oh you know who I'm talking about. The professor is talking about a piece of art: a painting, a building, the form of an arch. He knows what he's talking about, he's not looking for any form of affirmation. He doesn't need it. He has a doctorate. He has a job. He's your superior. He's studied this stuff for years and there's a pretty good chance that he's written a book.
But there they are, nodding in that "Oh yes yes of course, I knew that already" way. Nodding so much that I'm surprised they don't have neck or dizziness problems. At times the nod is so exagerated that the chest practically interferes with the motion. Said nods are frequently accompanied by a strategically placed "mm-hmm, mm-hmm" (up to 5 mm-hmms at any given time) uttered just a little bit too loud as to assure that everyone else knows that they know what the professor is talking about. Now I know this is hard to take, but "everyone else" doesn't care if you know or not. Your nodding does not make you appear smarter. And your nodding head is really quite irritating for people sitting in back of you trying to look at the projected slides. I know that I, at least, don't feel like synchronizing head motions with you in order to avoid seeing your bobbing dome piece in the middle of a barroque church.
So here's to you, over-anxious head nodders. Because if I were to lose a bobble-head doll, I could throw a Red Sox hat or a hula skirt on you and stick you on my dashboard.