I'm not the guy that is going to have a quick comeback or charismatic presence.
That's what she said....?
On the other hand, give me a couple glasses of whiskey and I probably won't shut up.
I think you are not alone in this - 5 million Finns... :D
However. it does point to the issue not being "you" and more about some kind of psychological block of some kind. Which also means it is likely possible to overcome it with the right practice. So, is anyone really an introvert or extravert, or is it just the role they play?
Yeah, that very well could be. I think as I said in another comment I might be worried about coming off as immature or not adult enough. Though that has been something I always had an issue with. A few weeks ago I wrote a post about not feeling like an adult.