If you have a choice (and you do) in whether to work with someone who is completely work-obsessed and someone else equally competent who has outside interests, which will be more fun? Furthermore, outside interests are vital to helping us get a better perspective. When I worked with the product engineers during the early days of Compaq Computers, the least valuable assistance to the advertising agency was provided by the engineers who knew the most about the product and the least about the outside world in which it would be used.

Oh, and please look over the entire article. It not only has great insight, it's fun to read as well.

Social Media Examiner: 7 Social Media Truths You Can Ignore and Still be Successful, 2010-June-1, by Rich Brooks

In fact, my interest in zombies is so well-known that friends tweet me zombie news and I’ve even received several zombie-themed gifts at events. It seems strange, but the undead have helped build my network.
While that may not lead to direct sales—Google Analytics still doesn’t list “zombies” as a traffic source—it has helped me make new connections and opened up new opportunities that have led to business.
While zombies may not be your cup of tea, sharing your interests—whether it’s gardening, cooking or skydiving—will attract like-minded people to you and help build your network.