“Research shows that workplace friendships can increase job satisfaction, productivity and job commitment while decreasing stress and turnover," writes Beth Azar of the American Psychological Association. This means that you can be friendly with your co-workers and make your office a more welcoming place for yourself. Be careful, though; when workplace friendships go bad, it’s usually because a co-worker didn’t live up to the expectations of friendship at work, by disagreeing with a work friend on a project or by giving a negative evaluation, according to a 2004 study published in the “Journal of Social and Personal Relationships."

To stay on friendly terms with your co-workers and still maintain productivity in the office, you should set clear expectations for professionalism. Explain to friends at work that you don’t want to favor friends over other co-workers, so you plan to be honest with them about work-related issues and you expect them to be honest with you as well. "If it's a good decision, and your friendship is functional, your friend might be disappointed but will understand," says psychologist Patricia Sias.

Now that you might be on Facebook, Twitter, and other social-media accounts both for work and personal purposes, it can be much harder to separate the office from your personal life than it ever was before. You need to consider what you post before accepting friend invitations from your co-workers, according to senior-level HR Professional Jessica Simko of Careerealism.com. If you’re always posting content like “I hate Mondays," she says, even if it’s on a personal account, it can backfire on you at work. Simko recommends that professionals block or restrict co-workers from personal Facebook profiles to minimize the overlap between work and life. Better yet, she says, don’t post anything in poor taste and you won’t have anything to worry about.

Even though some of your co-workers may become your friends, you still want to have a life. Make sure that your life doesn’t revolve around work, and that you maintain relationships with friends and family members who are not employees of your company. Go out regularly with your non-work friends to places where you are unlikely to run into co-workers, and talk about anything other than work. It will be easier to maintain a level of professionalism around your work life if you make the most of your time off.