happiness isn't just a state of mind. To be really happy, the happiness has to be grounded in reality, to be honest, to be fulfilling, to be useful, etc. In short, real happiness is an achievement of a moral goal of "well being". In short, a "happy fool" isn't truly happy. A person who has just been conned and think they "got a steal" isn't really happy. I like the Aristotelean formula: To live a happy life is to flourish.
I've long held the view that the Stoics were on to something. They lived in a Roman empire in which day-to-day life was precarious. It was cheap and unpredictable. The question of happiness was a pressing question. And they came up with pretty good answers. From Wikipedia:
Following Socrates, the Stoics held that unhappiness and evil are the results of human ignorance of the reason in nature. If someone is unkind, it is because they are unaware of their own universal reason which would lead to the conclusion of kindness. The solution to evil and unhappiness then, is the practice of Stoic philosophy — to examine one's own judgments and behavior and determine where they have diverged from the universal reason of nature.Here is the key bit of David Sosa's take on happiness:
Happiness is harder to get. It’s enjoyed after you’ve worked for something, or in the presence of people you love, or upon experiencing a magnificent work of art or performance — the kind of state that requires us to engage in real activities of certain sorts, to confront real objects and respond to them. And then, too, we shouldn’t ignore the modest happiness that can accompany pride in a clear-eyed engagement with even very painful circumstances.The wonderful thing about philosophical "problems" is that they are difficult nuts to crack. So they are a puzzle with endless amusement as you consider them again and again under different light and from different perspectives. They are the ultimate "mind games".