Ask yourself whether you are happy', observed the philosopher John Stuart Mill, 'and you cease to be so.' At best, it would appear, happiness can only be glimpsed out of the corner of an eye, not stared at directly.

Uncertainty is where things happen. It is where the opportunities - for success, for happiness, for really living - are waiting.

Reassurance can actually exacerbate anxiety: when you reassure your friend that the worst-case scenario he fears probably won't occur, you inadvertently reinforce his belief that it would be catastrophic if it did. You are tightening the coil of his anxiety, not loosening it. All to often, the Stoics point out, things will not turn out for the best.

The effort to feel happy is often precisely the thing that makes us miserable. And that it is out constant efforts to eliminate the negative - insecurity, uncertainty, failure, or sadness - that is what causes us to feel so insecure, anxious, uncertain, or unhappy.