You're a hard nut to crack, Zinny Taylor

I tell myself that I am simply hard to get to know. Or shy. Or reclusive.
It all boils down to the fact that I'm truly open with hardly anyone.
I tell myself that once someone really knows me, then I will become this interesting knowledgeable character, and I share everything with them. But I have known my two best friends for nearly eight years, and am I open and honest with either of them?
No.
Is there truly anything inside of me worth knowing? Or am I simply a empty shell, to be interacted with, but never valued?
What is truly inside of me, that which makes me tick? Why am I so dull around friends, and yet so full of life by myself?
Am I truly a loner?