Critics of positive psychology argue that the field is resistant to scientific thinking. Self-reported data on people measuring their own moods is always dubious. And international studies are difficult since the concept of "happiness" as we know it does not even exist in certain languages.
"Interpreting data can be a great problem," Ruut Veenhoven, the editor of the Journal of Happiness Studies, told the New Scientist in 2003. At that time, Mr. Veenhoven had recorded 15 separate academic definitions in English alone.
Today, positive psychologists will tell you that happiness is not about mood (which can change from moment to moment), but a more prolonged psychological state.
They prefer the term "subjective well-being," which refers to a person's overall cognitive and emotional perception.
When you get down to it, however, isn't our notion of a happy life little more than a flimsy historical construct anyway? As New School philosopher Jennifer Michael Hecht writes in her recent book The Happiness Myth, the reward for all our cognitive behaviour therapy and vigilant impulse control is an illusion, one that shifts like sand in the winds of time.
"We think of our version of a happy life as more like physics than like pop songs," she writes. "We expect the people of the next century to agree with our basic tenets - for instance, that broccoli is good for a happy life and that opium is bad - but they will not. Our rules for living are more like the history of pop songs. They make weird sense only to the people of each given time period. They aren't true."
Even if it was made up of fixed, measurable ingredients, there is a strong argument to suggest that this thing called happiness may not be the holy grail of human experience we once thought it was.
According to the New Scientist, countries that report the highest levels of happiness - such as the United States - also tend to have the highest levels of suicide and depression.
And researchers at the University of Toronto recently found that while happy people are more creative, they have difficulty focusing on simple tasks and ignoring distractions.
Perhaps our obsession with cheer is rooted in a sense of entitlement. Only a half-century ago, the question "Are you happy?" would have seemed ridiculously self-indulgent.
As Steve Salerno, the author of Sham: How the Self-Help Movement Made America Helpless, told me in an interview, "I once asked my father if he was happy, and you know what he said? 'A man doesn't have time to ask himself that question.' "
How times have changed. In the past, Ms. Hecht explains, people thought it was quite normal "to feel bad a lot of the time, and to break out and celebrate occasionally." Now, we expect, and are expected to be, happy all the time - a state of being as arbitrary and wrong-headed as many of the ways we go about attempting to create it.
Which brings us back to Freud's idea that maybe we were never meant to be perfectly happy in the first place.
As he writes in Civilization and Its Discontents, happiness is "from its nature only possible as an episodic phenomenon. When any situation that is desired by the pleasure principle is prolonged, it only produces a feeling of mild contentment. We are so made that we can derive intense enjoyment only from a contrast and very little from a state of things."
In other words, happiness, as a state of being, is fleeting at best. As humans, a restless contentment is probably the best we can hope for. A benign acceptance of life as it is, rather than an optimistic yearning for endless bliss.
"If we define happiness correctly, it has ups and downs built into it," Ms. Hecht says. "Just as we can't talk about a flat roller coaster, who would want a life of constant orgasm?"
Leah McLaren is a feature writer and columnist with The Globe and Mail.