Zazen is focus. Part of the art of meditation is learning to hone the mind so that it becomes single minded in the present moment. There are innumerable benefits to this including the development of clarity about your experience, listening deeply and attentively to others, sustaining focus through difficult times, centering your life in the middle of whatever you are doing, and relaxing in the context of a stressed out culture.
I like to think that every moment I miss in my life is a mini-death, a lost opportunity to be completely alive and intimate with the world. The look in someones eye, the requests of my child, the beauty of a tree or flower or rock; the whole of the world is a continual flowing and lyrical melody. There is a calm delight I have when I sit Zazen and am at peace with the world of the moment regardless of what might be tugging at my life.
To develop more focus requires a clear intention: you must want too! Then it requires practice and discipline, which can often be felt as a double bind: 'I don't have enough time already so now I'm supposed to take time to sit and just focus?'!. Yes, absolutely. Paradoxically, somehow slowing down is speeding up, and limiting your focus to the present moment increases the quality of life. At some point in practice meditation isn't an activity separate from what you are doing;- what you are doing each moment is meditation and the entire focus of your whole being.