I never knew writing was so organic

For the longest time I've only lived in my head and played around with ideas of stories and plot lines. This that and the third and I was great (so I believe) at coming up with interesting tales and characters. I could make a story off of a single thought, even so much as a single sound could easily spark my imagination into overdrive. I could rattle off about everything I've possibly thought of but since I pulled an entire continuity reboot and started from scratch that would be pointless. Back to what I was saying.

My most recent writings in the The Sentinels, which is an episodic story on a blog, has made me start to realize the writing itself is... living. Week to week I've got to expand the story and keep things on track and while I'm doing this I find myself saying "No no, she wouldn't do that." or "He/she's gotta make this happen" and I slowly started realizing that this stuff has a mind of its own. When it wants to expand it demands a new character or plot element. It demands a character act a certain way or a scene have a certain type of symbolism. At first I thought "ok... I've lost it" and perhaps maybe I have but I as the writer can't deny what the story wants. It's part of me, my creation so why would I neglect it?

That was just the thought of the moment, I apologize if this is like an obvious point for everyone or just plain insane. But that's what I was thinking.