Model: Influence vs Concern
There are things in your life you can influence.
There are things in your life you can't influence.
You can see this as a spectrum going from totally in your influence, to not in your influence at all.
Concern
There are things in your life that concern you.
There are things in your life you aren't concerned about.
This is also a spectrum from very much concerned about to totally not concerned about.
Imagine all the things you can influence as a circle.
With the things you can influence very much, near the centre.
And the things you can influence very little, near the edge.
Imagine all the things you might be concerned about as a circle as well.
Your circle of influence will be smaller than your circle of concern.
Circle of Influence
Circle of Concern
Now you can choose where to focus your energy:
If you focus your energy in your circle of influence.
When you do things you can do.
Your circle of influence grows.
If you focus your energy in your circle of concern.
When you worry about things you can't change.
Your circle of influence shrinks.
Eg.
When you make a plan on how to make money, your influence grows.
When you worry about not having money, your influence lessens.
Why is this model useful?
It makes clear that you are in control of where to focus your energy.
It shows that worrying about things you have little to no influence about, is useless and maybe even harmful.
(src: 7 Habits of Highly Effective People)