when i was in elementary school, i remember coming in from recess and wildly fanning myself with my hand to cool down. all the other kids in my class did this, too. on one of these occassions, my third grade teacher told us that the energy exerted on the fanning efforts actually made us hotter instead of cooler. therefore, we should stop.

looking back, i think this was a lie she made up just to get us to be still.