This applies to more than just computer geeks. You see this in any specialized profession, especially ones that require great technical prowess or accomplishment. That's right, even doctors and lawyers can be like this. In some cases it's being known as a team player, or just personable, or having good bedside manner. Often times, this is how people unfamiliar with your profession measure your ability. If you have good bedside manner, then you must be a skilled surgeon. If you can relate well to a client, then you must be able to write wonderful briefs. If you're not a cubicle recluse, you write great code. Of course this is entirely false. In fact, often times it's the exact opposite. People who are the most introverted are often times the most skilled at their profession. But because they come off as shy, or maybe even rude, it's assumed they must not be good at what they do.
In my experience, some of the most clever, most skilled programmers have been very introverted, and very reclusive. They're the type of person who sits in their cube, and won't interact with you unless they have to. But the code which they produce is very high quality, and they have a very deep knowledge of software. Having spent part of my career hanging out in hospitals, I don't know how many times I've heard from nurses about about a doctor with terrible bedside manner, who was the best surgeon they knew of. Often times I think serious professionals tend to sacrifice the development of their interpersonal skills in order to concentrate on the technical aspect of their job.
I write this for two reasons. First, it's important to recognize this about yourself if you know you are this type of professional. People will judge you, fair or not, based on your ability to communicate well with others, even if it is not the most important part of your job. Of course, the ability to work well with others, and communicate effectively with patients or clients ought to be a highly desirable skill anyway, and so if you should recognize that it is a reflection on you, and try to improve.
I also write this to make others aware of this. Don't judge someone purely based on their interpersonal skills. While it may be important, it's often times not the most important skill to have for a position, and you may be passing up on someone who would do an incredible job for you. Moreover, someone who can talk a good game my not have the chops when it comes down to actually doing the job you hired them to do. Don't use one as your only measuring stick for the other.