My breathing's a fairly straightforward process: I inhale, I exhale, and then the whole cycle repeats itself all over again. It's a pretty good setup this thing called a respiratory system, and if nothing interferes with its course of action, I'm pretty sure it'll just carry on doing its thing without me ever having to give it another thought.
So, what would be the point of hanging a poster with the word 'breathe' on it if every time I stopped and looked at it, it would remind about my breathing, after I just said thinking about it wasn't necessary for its function? Well, it's because that's exactly what I would want to do ― stop and be re-minded. No, not so that I'd pause my daily activities and think about my lung's ability for handling air, but instead to take a pause, focus on the rhythm of my breathe, and then gently slip into an air of Mindfulness – a higher state of Consciousness – my Peace.
Yes, that's right, breathing is a great tool to use for changing one's attitude; one's mindset. One such means for this concept is the breathing practice called Praṇayama. It's a process where if you can control your breathing and still the mind of it's thinking, you can potentially attain higher states of awareness. 
I've actually been known to practice this type of breathing and I've found it very effective, however I will also tell you, as effective as Praṇayama is for me, there never seems to be enough time to sit and dedicate the effort it deserves. It's perfect as a structured spiritual exercise, but in my opinion, it's not the easiest to incorporate long periods of breathing meditations into a contemporary lifestyle. It works, but not so much when one is at work. When verbal sparks start flying, you can't exactly sit for half an hour cross-legged on a boardroom floor with your eyes closed and breathing deeply through alternating nostrils, just to gain some peace of mind. Unfortunately, the goal to reach my enlightenment, by using this process, has to wait for weekends. No, I'm talking more along the lines of using the breath as an immediate connection to the Mind of Peace wherever I'm at and whenever. I guess you could say, it's when I'm in a lower state of awareness, as in, not a note of peace can be found anywhere. Hence the stress, and hence the need for notes of reminding like on a wall print.
Now, what I do find effective during the moments throughout the day that cause distress or frustration, is an activity that doesn't really have a formal caption. I suppose there are all kinds of people out there who could identify it and give it some type of creative label or tell me that there's not point in naming it because it's an ancient practice from the mountain region of... and it's called... And that would be great if they can, but I'll just tell you, for me it's known as, Breathe. That's right. If I quietly breathe in and out, and watch the whole rhythmic process with intent, as in, be mindful to the harmonious movement of my lungs or the air passing through my nasal passages, over a short period of time, seconds even, my Consciousness makes me aware that I'm no longer restlessness and I'm now in a state of contentment. In fact, if it's done sincerely, my thinking mind, that set the whole unsettling emotions into motion to begin with, will have become so distracted by the breathing, it will have forgotten why it stirred up a state of distress in the first place. This is key, because this is what opens up a space in my mind for the wiser part of me, my Mind, with a capital M, or Conscious Intelligence if you prefer, to get a solution or new idea through.
I have no official way of confirming whether my breathing approach is actually slipping me into a higher state of Consciousness, but I can tell you that I am very aware that these mini moments of calm feel like a breathe of fresh air during times of stress, and if that's not heaven, then I don't know what is. And that's why I thought some calligraphy art, with the word 'Breathe' on it, could bring to mind, some peace.