As loathe as I am to appear all introspective and navel-gazing, this discussion has got me feeling like I have to speak out.
I'd have to say that my extreme shyness, which runs to the point of being painful at times, results from reasons 2 and 5 listed above.
I was in my mid-teens when I realized that performing music before a crowd was easier than meeting a new person and having a one on one conversation. After much thought, I decided it was the physical act of having a guitar between me and them that did the trick. I felt safer and could channel some of my concentration into what my hands were doing with the instrument, and direct it away from concern about what the audience thought about me.
A natural outgrowth of this was my entry into acting. In that arena, I find I can keep the playwright's words between me and the audience. So, even though, I'm using my real emotions to convey the feeling, they're not really my words, so it's safe to say them.
Fortunately, as I get older, and pay more attention to the lessons life teaches, I'm getting better at recognizing my own value as a person and am getting somewhat better about being shy. Both in terms of overcoming the most extreme aspects of it, as well as coming to terms with the fact that I just am a shy person and that's an okay thing to be.
A deep breath and back to it...