I heard this while listening to Dale Carnegies How to Stop Worrying and Start Living (Nice summary in Wikipedia, btw)
Worrying happens when we have a moment to think. This moment usually isn’t the result of taking a break to relax, but rather a moment in the middle of stagnant life situation – when you aren’t mentally engaged enough.
You can rationalize all you can, but sometimes the worry is still there. It seems that you can’t do anything about it.
You may have tried to do something to distract yourself: cleaning or some other task. The thoughts are still there and you feel like giving up.
The difference between “worry-dissolving” action and action that doesn’t help is the degree your mental engagement you are experiencing.
Think about it: when you are doing some menial task that you can do automatically, your pre-frontal cortex has “free space” to start thinking about all the shit in your life.
When you are engaged in something that really REQUIRES your thought processes and intense focus, your mind doesn’t have any chance to start spinning the worrying thoughts. For example for me writing, drawing and doing analysis engages my mind easily.
This was a great point in the book and I thought that it was worth sharing.