My problem with the extraversion/introversion dichotomy is that I'm not either extreme. I am far too introverted to competently fulfil my basic social needs without some form of passive socialising like having an office full of people around me. I don't thrive with going out on the town and making friends like extraverts I know. But I'm definitely not the type of person that can not speak to people for weeks. I think that sort of person is sort of rare and should not be the basis of the entire system. I honestly think that level of introversion is not what most people even mean when they talk about introversion. That is highly unusual and is not how human nature usually works.