Taking control and insisting on it is not polite, unless you the boss. It is pretty bad trait for college in cooperative environment.

I've been out of college for ten years this month and I can still remember those few students who could not get it through their head that class was not a one-on-one conversation between them and the instructor.

My favourite professor: “I’m glad you found my paper on Chaos Theory interesting but my Numerical Methods class is not the place to discuss it. Please stop interrupting me.”