While in a productive mindset, it is easy to value your time more over social activities, relationships, and friendships. You think more about the work to do rather than the friendships you need to maintain. I have fallen into this disarray where I do not spend any time wondering about other's well-being and maintaining those friendships. What can be done to strengthen the social aspects of your life without breaking too much away from your productivity?
I would rephrase the question to help drive the outcome you're looking for. How about "How do I include developing and maintaining relationships in my productivity system?"
There is a terrific article on this topic at http://www.marshallgoldsmithlibrary.com/cim/articles_display.php?aid=157 The summary is that everything can be measured, if you create a metric and watch it, you can change your behavior. It is not a long article, well worth reading.
The trick is to figure out what metrics you can use to help you define success in productivity terms. You could set a goal of N minutes on the phone with friends and family a week, or N thank you notes sent, or lunch out with someone every week. Think a little creatively, and you can find something that will make creating and maintaining a healthy social life a part of your productivity system, instead of something else to do.
Going by your description, it seems that you are in fact a very productive individual and follow your system strictly. With this in mind, you could try the following approach.
A simple (but not easy) thing you could do, is to create small intervals in your usual workday lasting about 5-15 minutes each specifically for socializing. In those 5-15 minutes, you could :
All of these activities will activate your empathy and and strengthen your relationships with other people.
Sometimes, having an overly productive mindset may mean that you would look at these intervals as being unproductive. To tackle this, think of this as a part of increasing your social resilience which in turn will help you perform better at in your day to day life. If this line of thought doesn't motivate you to incorporate these sessions into your daily schedule, then just think of these sessions as something you have to do, similar to your work. This way you would (ideally) concentrate on only the person in front of you at the time, similar to the way you would focus strictly on work.
Hope this works out!