It's interesting to hear managers say that people leave because of money but that's far from the truth. Sure, there are some people that need more money and they look for new opportunities simply because of that reason. The reality is that it's not near as common as people leaving simply because of the people they work with and it's not limited to just co-workers but their managers as well. People will even take a reduction in pay to work in a better environment and with better people.

If an employee isn't happy with the people they see more than their own family then they're not going to stick around and be miserable.  

Get to know your staff and you'll be surprised to find that there's at least one person stirring up problems in your office. You can't address that which you're not aware of so make effort in understanding what your staff deals with and what frustrates them. If you feel that there are problem people in your company then make effort to manage their behavior. The answer isn't to terminate people who don't seem to get a long with others but that could be an end result if proper counseling doesn't improve the unacceptable behaviors.

If you fail to address problem employees who create negativity in your workplace then your staff will start to lose respect and trust in you as an employer. If they feel you're ignoring the problem and allowing it to occur then that alone will start pushing the frustrated employee(s) to look for new opportunities.

Be proactive and manage the people you have to minimize the risk of losing people simply because of the work environment.