"Calmness of mind does not mean you should stop your activity. Real calmness should be found in activity itself. We say, "It is easy to have calmness… - Shunryu Suzuki

and you will become friendly with others. This is the merit of Zen practice. But the way of practice is just to be concentrated on your breathing with the right posture and with great, pure effort. This is how we practice Zen.

You should not have any remains after you do something. But this does not mean to forget all about it.
In order not to leave any traces, when you do something, you should do it with your whole body and mind; you should be concentrated on what you do. You should do it completely, like a good bonfire. You should not be a smoky fire. You should burn yourself completely. If you do not burn yourself completely, a trace of yourself will be left in what you do.

The true purpose [of Zen] is to see things as they are, to observe things as they are, and to let everything go as it goes... Zen practice is to open up our small mind.