You can't force your employees to be positive people.

Hiring is obivously one of the most important things you do as a business leader, and managing your workers is so much easier when they are positive, hard-working and happy people.

We all know that there is a certain amount of negativity in every workplace. And, it turns out, there's not much you can do from a human-resources perspective to get rid of it.

In fact, now by law, you can't force your workers to not be negative.

The National Labor Relations Board says that workplace policies requiring employees to behave in a "positive and professional manner" actually violate federal law

One employer, a non-union hospital, set up a workplace policy that expressly banned “negativity or gossip.” What's more, the hospital said employees had to represent the hospital "in a positive and professional manner."

One worker sued, saying such policies infringed on employees' rights. Ultimately, the NLRB said policies that require "positive and professional" conduct are unlawful, since they could limit protected activities, like political speech.

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So are you destined to be saddled with negative employees? Not quite. Obviously there are ways around the NLRB's decision. For one thing, while you can't force people to be "positive," you can still take behavior, particularly how it pertains to interfacing with customers or colleagues, into consideration when doing employee evaluations. For instance, while you can't fire someone for gossipping, you can say that the time an employee spends talking smack about a colleague by the water cooler represents time he isn't spending at his actual job.

Secondly, it makes trying to gauge a potential employee's positive attitude even more important during the hiring process. Weeding out bad workers isn't necessary if you on-board the right people in the first place.

Still, most entrepreneurs are laser-focused on company culture and know that, particularly in smaller workplaces, it is great to institute actual policies to protect that culture from negative people.

Instead, being positive has to be left unsaid, thanks to government intrusion and regulation. That seems like the biggest negative of all.

Related: Why Americans Don't Want to Start New Businesses