Your duty as a business owner includes ensuring that you've taken every possible step toward maximum productivity. Part of this concept is the overall design of your office. It's possible for a workplace environment to feel overly sterile and uninviting if no attention has been paid to the layout of the furniture or the room itself. Once you've struck a good balance that promotes innovation and creativity, your employees are more likely to feel more comfortable, decreasing their overall stress and boosting their productivity.
First off, consider the configuration of the workspace. Do you find that your employees have to squeeze by each other to get to their desks? Cramping of an employee's personal space could potentially bring down their productivity level, or even negatively impact their morale. Experiment with different configurations, and consider allowing the employees to come up with a solution as well. Some business advisors don't advise "letting the prisoners run the asylum," but it's important to remember that employees respect employers that give them the freedom to choose their most functional work environment.
Also, zoning different areas of the workplace could help your employees subconsciously spend more time doing "true work" and taking "true breaks." Bring a couch into the office and set up a break area for employees that need to take a break from staring at glowing screens all day. That way, when they get back to their working station, they'll feel refreshed and ready to get back to their work.
Whatever you do, it's important that you experiment with different methodologies, and also take your employee's suggestions to heart. If your employees haven't made any suggestions about how to improve the workplace layout, remember that it may be out of fear that they'll be seen as a whiner. Organize and revitalize the workplace for them so that they don't need to feel uncomfortable when they should be the most productive.