If you take enough classes, you're going to get a lot of instruction on something you've already been doing relatively successfully since the moment you were born: breathing.

Lay on a Reformer and you'll be asked to breathe into your back ribs. Lay on a yoga mat and you might be told to let your belly expand. Another teacher might ask you to breathe through your nose while making a sound like the ocean in the back of your throat. And then one day you try a rapid breathing practice with an intensity that feels somewhat at odds with the word "yoga."