Sometimes we find ourselves mulling over something which is bringing us down. We generally think that enumerating every little thing about what ever is bothering us will help us to find a solution to the problem. The truth is the more we recount and retell, the more we think of even more things to be grousing about. This is an aspect of the Law of Attraction which will then cause us to spiral down on the issue even further, which ends up making it worse while also attracting other similar scenarios forward into our experience.
The key is to stop ourselves as soon as we realize what it is we are doing. Instead if we begin a slow rant of appreciation for something - even if it's not on the same subject or even close to it, the movement within our mind will be shifted over to a more positive, grateful stance.
With this shifting of our energy, eventually the issue we were grousing about will fade from the picture. Now it is no longer be being "fed" by the thoughts we were so eagerly providing it to grow by.