Youth, the old saying goes, is wasted on the young. And apparently, the data backs this up.

Looking back, your 20s might seem like a carefree period of music festivals, dubious housekeeping standards, career experimentation, and generally unabridged freedom. But when happiness app Happify combed through the data generated by its product not too long ago, it found a reality that belied such stereotypes of carefree youth. According to this large, if specific, data set at least, your late 20s are likely to be the most miserable years of your life.

Why might that be, Happify wanted to know, so they recently performed a series of follow-up investigations, analyzing thousands of responses to several of their writing prompts to uncover what's troubling twentysomethings. In short, the answer seems to be an excessive obsession with work.

Professional concerns dominate.

In a detailed post on the HBR blogs, Ran Zilca, Happify's chief data science officer, explains how the company went about exploring what topics were particularly common among Millennials' responses to questions about gratitude, long-term goals, and short-term goals.

While all age groups often had similar responses -- everyone seems to want to get better at managing their time, for instance -- younger users were particularly likely to talk about their work in response to all three writing exercises.

"The topics for which Millennials specifically expressed the most gratitude were different: 'positive interactions with colleagues,' 'having a low-stress commute,' 'getting a new job,' 'being satisfied with an existing job,' 'sleeping,' and 'relaxing in bed,'" writes Zilca, for instance. Analyses of prompts related to goals turned up a similar focus on career concerns, as well as a consistent interest in personal wellness.

So what?

It's probably no surprise really that those are the very start of their careers are stressed about their work, so beyond confirming that the quarter-life crisis is real, what if anything fresh can we learn from these results? Zilca suggests the most insightful findings might be more about what Millennials don't mention when discussing happiness and goals than what they do.

"Millennials are quite aware of the stress in their lives, and they seek ways to reduce it. They attempt to do so by following a workout regimen and by spending some relaxing time in bed," he says, which sounds healthy enough. But according to Zilca, there may be better methods of stress reduction that Millennials are missing out on.

"We find that Millennials do not tend to mention close relationships with family and friends as a goal or as something they appreciate. This too is supported by previous research, showing that the goals of young individuals are shifting away from community, affiliation, and civic orientation, and toward individual success," he writes. "One cannot help wondering if spiritual life and social life are not the missing ingredients that could make Millennials happier."

Professional stress might be somewhat inevitable when you're first finding your career footing, in other words, but young people are probably doing themselves no favors by making work achievements alone so central to their pursuit of happiness. And while hitting the gym or regularly unrolling that yoga mat is certainly not a bad way to deal with the anxiety of a new and precarious career, Millennials might be happier if they thought of connecting with others as just as vital to success as climbing the career ladder and staying fit.

(Though don't worry too much about angsty and anti-social young folks -- other research suggests their definition of happiness and success will shift as they age.)