Degrading social skills

I was blown away by an old friends accusation that I was both angry and annoyed with them. I have apparently forgotten to return phone calls and looked annoyed at their presence at a recent coffee meeting with another friend. I really hadn't realized that I was projecting these feelings towards them and it has got me thinking again about the effect of being totally immersed in the graduate student life.

Could living and working as a graduate student be degrading my social skills?

I've commented before on the strangeness of this life. The loneliness, stress, and change in thinking that you feel as a graduate student. In my life I have met a few people who are considered "over-educated." People who have pursued their education to the point that they seem incapable normal social relationships and are unable to find regular employment.

So, my question is: Are these "over-educated" "unemployable" people this way because they continued their student life beyond what is considered a normal length of time? Or do those people pursue further education because of some pre-existing social inadequacy or awkwardness?