Apart from being essential to life of course!! Actually having a more concious awareness of your breath i.e. whether it has become fast and shallow, or being able to slow and deepen your breath as a poweful tool to relax and revitilise - I explain more about this here..
Now you have a better understanding of how breathing can be used as a poweful tool for relaxation here is a very simple and easy one to try - this works even if you've not had success with breathing techniques in the past, and is something you can do ANYWHERE, on a train, in your car (not driving!) or at home.
Let me know how you get on x