You may even have plenty of friends and colleagues. But if you work at home or on-site for a mixed bag of clients, there is no regular commute, no coffee break chitchat, no drinks after work. Your work may rarely require that you interact with anyone. Your work can suffer, especially if you feel uninspired, unappreciated or not in the swing of things feelings that simple social interaction can help correct. Along the same lines, your business can suffer.
Prolonged isolation can lead to social phobias, even depression.
This can be as simple as picking up the phone. Regular contact with friends, family, and colleagues will keep you in touch with what's going on the lives of those around you and allow you to share your own thoughts and experiences. Be a social professional. In the old days, it was the three-martini lunch that ran into the late afternoon and was paid by a corporate expense account. Now, this just means meeting other professionals on a regular basis socially.