If, say, you are concentrating on an important problem, all of your thoughts and feelings will be engaged by that problem. You become the problem. By identifying with the problem, you gradually solidify its reality around you, cutting yourself off from other energy.
As you identify with the problem your feelings become clouded, and you will find that you cannot see the forest for the trees. New energy finds no opening to refresh you. The reality around you reflects only the countours of the problem in which you are immersed. The solution must come from what you believe, since that is the only reality you can perceive at that time. The same logic applies to your life. Each event ratifies your experience and that experience settles in your consciousness like a block of concrete, every bit as real.
The feelings you generate pull you into areas of the physcial plane that match those feelings and they will dictate what you will choose to do day-to-day.