Who are America's happiest workers?

Ever wonder who are the happiest people in this country? Those with a job -- or even a second one. And among those who are employed, it seems the self-employed are the happiest, by a slight margin over freelancers, according to a survey of 1,000 working Americans.

About 53 million people are now in this "nontraditional jobs" category, according to the Bureau of Labor Statistics (BLS).

Conversely, who are the unhappiest? If you guessed those who say, "You want fries with that?" or those balancing trays for base pay plus tips in the food service industry, you're right. They register more than a point lower than the self-employed on the seven-point happiness scale. 

In the middle are salaried workers and just below them hourly workers, according to a survey by insurancequotes.com, a website that describes itself as "all things insurance."

Job stress was higher among self-employed and freelancers given their fights to get new gigs, but other factors made up for it, like "work environment" (sitting down at the job in your pajamas) and "flexibility" (going fishing on the sunny days of summer).

The broad-ranging survey on "Workplace Well-Being" also looked at the virtue -- and vices -- of having a second or side job to supplement income, particularly for those whose main job's salary doesn't cover all the bills. Surprisingly, the survey found that in terms of job flexibility, those with more than one job were nearly 10 percent happier than those with only one. 

That encompasses a lot of people. According to the BLS, about 7.6 million people have more than one job, including a third of millennials.

Work/life balance, as well as job stress is about the same for both groups, but those with only one job made more money, earning a 7 percent higher pay rate.

But the all-important area of health care showed a big difference. Nearly two-thirds of those with only one job felt comfortable paying for a routine medical checkup, while only 58 percent of those holding multiple jobs did.

The same could be said for starting a family. One-third of those with only one job felt confident enough to do so, while only a fourth of those with more than one source of income did, perhaps because two jobs would take time away from the spouse and potential children.

When it comes to working secondary jobs, millennials are the only generation who'll work for base pay plus tips, in addition to their primary jobs. And the oldest generation still employed, baby boomers, are more likely to freelance or work for themselves.

Those surveyed by insurancequotes.com had surprisingly low salaries in their alternate careers. On average, both millennials and boomers earned a median salary of $100 to $149 per week from their second jobs. Close to 10 percent of the younger workers earned less than $50 a week -- which could be why they live in their parents' basement.

But this extra money may be helping the parents as well, thereby making both Gen-Xers and boomers happy.