Do you have a lot of activities outside work? Maybe you volunteer for various organizations. Or perhaps you participate in charity events like fun runs and fundraisers. Maybe you're in a band or perform as an actor. These and other activities show that you're contributing to your community. They also show that you have interests outside of the office.
Showing your boss that you participate in activities outside the office can help you when you enter discussions about balancing your work with the rest of your life. If you can demonstrate that you're making a positive impact outside the workplace, you may be able to leverage that into a more liberal work policy. That could mean anything from flexible work hours to teleworking during part of the week.
Keep in mind these activities are positive. If you spend all your time outside the office carousing, goofing off or causing trouble, you won't want your boss to know about it.