A great little video on the physiology involved with breathing, and some of the downstream effects of the different methods. Pretty common knowledge by now, with Yoga having hit the mainstream and all, but science backs the benefits of deep breathing and making proper use of the diaphragm.
The trick is to cultivate a practice of breathing deeply at all times. Helps with stress, physical pain, becoming less reactive, maintaining energy, calm and focus. It’s almost crazy that such a small change can have such significant impacts.