If we allow ourselves to focus on variables outside of our control, we invariably take the focus from things we can change. In other words: When you think about things outside of your control, you take resources away from things that can make your life better.
You have a finite amount of time and if you focus on that you cannot change, you steal time away from actions that bring change to your life.
IF: You focus on what you cannot change
THEN: you steal time away, from actions that bring change.As you focus on what you control, your circle-of-influence (what you control), increases. Inversely if you focus on what you cannot change your circle of influence decreases.
Focusing on variables outside of your control is stealing time from the finite amount of time that you have left.