A big chunk of American workers have checked out from their jobs -- and are thinking about ending the relationship. That's troublesome for employers. Study after study shows that companies with engaged workforces outperform their competitors. Conversely, low morale saps the bottom line. If people don't like their jobs, they're less productive or quit. And replacing them is expensive. Fortunately, employers don't have to set aside two months' salary and get down on one knee to engage their workers. They simply need to change the way they interact with them -- and give them more control over their work environments.