Life has aspects we cannot change about and worrying simply comes to nothing as Mary Oliver suggests. There are many things we do not control even when we think we can. It is important to let go and recognize these phenomena as part of the unfolding of life.
Although Mary Oliver includes phenomena outside our control, she includes advice on how to deal with the lack of control. We can go out and sing or act in ways that are creative and life-giving. We can accept the world as it is and not try to correct it. Nature will do what she naturally learns to do. Our role is to be in the world, live in it lovingly, and attempt to do no harm in our living.
We control certain phenomena in the sense we can avoid what is destructive, but there are things that we learn and taught in living naturally.
I worried a lot. Will the garden grow, will the rivers
flow in the right direction, will the earth turn
as it was taught, and if not how shall
I correct it?
Was I right, was I wrong, will I be forgiven,
can I do better?
Will I ever be able to sing, even the sparrows
can do it and I am, well,
Is my eyesight fading or am I just imagining it,
am I going to get rheumatism,
Finally I saw that worrying had come to nothing.
And gave it up. And took my old body
and went out into the morning,