While Millions of People

are extremely unhappy being unemployed, those that have jobs aren't much happier.

Job satisfaction is at an all-time low:

"It says something troubling about work in America. It is not about the business cycle or one grumpy generation," says Linda Barrington, managing director of human capital at the Conference Board, who helped write the report, which was released Tuesday.

If the job satisfaction trend is not reversed, economists say, it could stifle innovation and hurt America's competitiveness and productivity. And it could make unhappy older workers less inclined to take the time to share their knowledge and skills with younger workers.