Why does the mind always want to 'do something' and how to cultivate 'non-doing'?

There is a Zen saying , 'Sitting quietly, doing nothing, Spring comes, and the grass grows, by itself' by Basho. But I have observed the nature of my mind that it always wants to '**do something**', it finds respite only when I apply it to solve problems. Why does doing nothing just sitting makes me feel like I am wasting my time? OR am I taking the teaching of Basho in the wrong way? How can I train my mind to **just be**? Edit: I am asking about all the time when I am not meditating.