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Depending on where we concentrate our attention we may feel happy or sad, optimistic or hungry, titillated or irritated. Depending on where we place our attention we may spend an hour agonizing in a problem, reliving or planning a sexual conquest or pondering on our most essential and serious concerns - each of these possibilities having it's own chemistry and kind of satisfaction as well as potential results and implications for the future.

taken from: 
How to Get Out