It is proof that positive thinking can do wonders. I have been doing something similar since working on my short stories book to give me motivation and inspiration to continue on no matter what. It really does help because you are thinking or typing a positive message every single day.
If you do not do this then you should really consider it. It can be a goal you want to meet or a simple message to yourself to remain positive.
If you try it, or have tried it, let me know how it works/worked for you!!