I find it weird that on committees, senators say "thank you" to the chairman when they get the chance to speak, or when they cede back time.
What are they thanking the chairman for? For example, is the chairman being in some sense generous by letting them speak (e.g. does he have the power to just refuse arbitrarily)? Or is the chairman responsible for the schedule and they're thanking him for the work gone into that? Or is it something else?