It turns out that in terms of happiness, the big divide in America is not between believers and non- beliefers, or Christians and non-Christians — but those who are certain and those who aren’t.
A recent study by Grand Valley State University found that ardent atheists were just as happy as ardent believers.

Those nonbelievers most confident in their nonbelief tended to be the most emotionally healthy, relative to the “fence sitters” who reported more negative emotions. Similarly, life satisfaction was lower among the spirituals [seekers]….Therefore, having uncertainty regarding one’s religious views appears to be associated with relatively greater emotional instability.”

The author reported that atheists who proudly identified as atheists were particularly happy. This makes me think that happiness stems from a sense of belonging. Atheists who have a clear identity find happiness in that certainty. This reminds me of how similar Bill Maher seemed to the True Believers he mocked in the movie Religulous. There’s great joy in knowing who you are, what you believe, and who your enemy is.
I wonder, though, if part of the problem is that there’s a social stigma on uncertainty. Consider the implicit condescension in the author’s term for spiritual seekers, “fence sitters.” Instead of being cast as curious, truth-seekers on a winding spiritual road, the undecided are sometimes considered “lost” or weak. In some cases, straddlers may feel disloyal as they’re rebelling against some family tradition. And it’s much harder to find a collection of kindred-spirits (membership numbers have not risen for the National Association of People Who Can’t Quite Decide What Religion They Are).
Finally, for those wanting a connection to the divine, the inability to establish it can leave a great hole — like someone unsuccessfully seeking romance. You can feel like a failure.
What are your theories for why spiritual seekers might be less happy than ardent believers or atheists?