We all have times when we are not at peace. Peace with ourselves, others ... the world. If we are honest the lack of peace always comes from within us. I have tried many times to deny that it comes from me and blamed others for my lack of peace, saying that the world is responsible. Violence, Jealousy, Envy that affect me is not my fault right!? There is nothing I can do to avoid it right!?... and so me not having peace is not my fault but that of others who pass their stuff to me right!? No ... wrong. Your peace, our peace, my peace comes from within my. It is my choice, it is the only true choice I have but it is always a choice.

I can't choose how someone else will treat me, but I can always choose how to respond and it is my response that will bring me peace or not. When someone is cruel towards me I can choose to become vindictive, defensive or hostile, but whatever my choice it is my choice.
If you want more peace rather look at why you may have responded. What within me was triggered, what memory or experience just responded and why I am still wounded by it. Now ask if the choice to respond is still appropriate. Ask yourself if you want peace or the drama that follows a knee jerk emotional response.
Choose peace, choose to think inside of yourself first and then choose the difficulty of letting go of your own internal hurts long enough to get through the moment and you will see that you gain the peace despite the fact that the circumstances don't change.
Now don't get me wrong, this is not about not acting, this is in no means a way of simply lying down and taking everything that comes at you. No. This is about have the peace within yourself that can not be taken away. It is about having the calmness, the peace, in the face of cruelty or difficult circumstances.
Breathing helps release seratonin into the brain, which stimulates creativity and restfulness a peaceful like state in the body, from which decision making is more clear.