I know of introverts who dress all in black, some even with punky hair. The message is clear -- keep your distance! They are letting the world know that they don't want interaction. With other kindred spirits, they live cocooned in a world of creativity rich in music, art, and fantasy. But that's not me.
I know of other introverts who quietly and steadily do their job. They live contentedly taking pride in their tremendous ability to manage details and in their immense capacity for concentration. They prefer to work alone and they accomplish much. Sometimes they enjoy being around people, and listening to others talk, but generally you will find them in a quiet corner talking details with another person like themselves. The don't need much interaction. If communication is required, they prefer that it be written. When necessary they will frugally measure out a few spoken words. My husband (ISTJ) is like this, but I'm not.
I know of some introverts who spend their lives quietly serving people. These (ISFJ and ISFP) practical people oriented introverts gravitate to occupations where they can quietly interact one on one in fields such as health care, child care, management, and homemaking. They concentrate their energies on doing things for people. Quickly tiring of relating, they retreat into action. "There is always something that needs doing!" is their motto. That's not me either.
I'm not much of a doer, though I do value helping people. I need quiet time to think, but I can't shut out the world around me. I love the arts and enjoy getting lost in a good fantasy book, but I don't want to shut myself away. I love people. I feel concerned for them, emphasize deeply with them, and desire to help people grow. I am the natural teacher and mentor. I like to observe people and try and understand the patterns in their lives. Like other introverts, I need time alone to think, and I enjoy deeply relating with one person at a time. I cannot just work alone for I need input, to talk out problems, and to share my ideas.
I am an INFJ. Though I need to relate deeply with people, I also need considerable time to process all the information I have received from the world around me. I need time to see patterns and create new ideas and solutions to problems. If I am not around people enough, I can become lonely and depressed. If I do not have the time alone that I need to recharge and create, I can become exhausted.
I don't want to scare people away, neither do I have my own natural armor to shield me from the world like my husband has, an ISTJ (all ITs). I can't just busily do like the introverted sensing people (ISFJ, ISFP, ISTJ, ISTP). How do the introverted people who are not thinking or doing types survive in society? Other types avoid overload by concentrating on details, or they engage in action, I feel that NF's have only one recourse- set firm social boundaries.