Nowadays I know what people meant by it. They thought I was shy, and by "shy" they meant fearful. The nice ones said that they wanted to help get me out of my shell, but they misunderstood me as much as anyone else. I wasn't shy. I don't like that word; most often it means "timid", and that's not an accurate way to describe introverts. I'm not saying that some introverts aren't also shy. I'm saying that the two terms aren't synonymous.
I never considered myself more fearful than the next person. Sure, I was nervous when I gave presentations in front of groups (waiting to stand in front of class was awful); but I was perfectly comfortable talking with people one-on-one. Yes, I became overwhelmed when there was too much socialness, but I wasn't afraid of it -- I just didn't know how to operate in those situations. I was categorized as a timid person, though, and for a long time I thought that really was a problem I needed to fix within myself.
It wasn't.
On the other hand, I probably do have a shell, of sorts. Who doesn't? Mine is not a shell made of fear, however; it's something equally natural, but definitely not anything that needs to be discarded. I think we introverts live "in a world of our own" for two reasons: first, because it's instinct, because that's where we're able to feel most like ourselves, and, second, because we're overly sensitive to the rest of the world, and we're worn out easily by it. Maybe these two reasons are one and the same, actually. We construct limits to help ourselves out, to get ourselves back to our inner "worlds"; we may as well call these limits "shells."
But that's not fear. I'm just as brave, and just as confident, as anyone can be. And I'm just as fearful, too. I'd rather not be boxed into the shy category, though; I'll define who I am and what kind of shell I have. I'm not hiding because I'm afraid. I'm hiding because it's required of me by nature. Or, well, that's more or less what I think, anyway.
If I'd known better back then, I would've questioned my supposed shell less; I would've been more proud of it.
Some lyrics:
Love me, love you
Loving is the way to
Help me, help you
Why must we be so cool, oh so cool?
Oh, we're such damn fools...
-- Supertramp