Gratitudes can make miracles happen

How can "Gratitudes" make miracles happen?
Sometimes you don't need to know why something works, you just need to know it works. When you switch on your car, it drives You can get from point A to point B. Not implied that you should know how an IC engine works. Same is the scenario for writing your gratitude every day. No at all its compulsory to know its reason why its happening but as said, the results speak for itself. Its tried and tested, what else you need then?
Spare out a few minutes and tune in your earphones to see how gratitude works out or say how it "IMPACTS" if you pen them down each and every day.