[...] we cannot reach happiness by consciously searching for it. "Ask yourself whether you are happy" said J.S. Mill, "and you cease to be so." It is by being fully involved with every detail of our lives, whether good or bad, that we find happiness, not by trying to look for it directly. Viktor Frankl, the Austrian psychologist, summarized it beautifully in the preface to his book "Man's search for Meaning": "Don't aim at success -the more you aim at it and make it target, the more you are going to miss it. For success, like happiness, cannot be pursued; it must ensue... as the unintended side effect of one's personal dedication to a course greater than oneself."
From Flow by Mihaly Csikszentmihalyi.