Why writers so often talk about their work

I'm acutely aware that many writers will at inappropriate times blurt out comments about a work in progress or a recently finished work; I'm one of those writers. I try to control it, but it does happen. I fear that it comes across as egotistical, and I know it is often, as I said, inappropriate to the discussion at hand.

So, I thought I'd explain why we do that: we're constantly living in multiple worlds, and sometimes the barriers between the two break down.

I know "living" sounds too strong, and in one sense it is: I never confuse the worlds I create with the real one. I live in the real world; I create other worlds. That said, my mind spends major parts of its waking (and often sleeping) hours in the worlds and the stories I'm writing. I don't see how to write well without doing that. Sometimes, the sheer amount of mental energy you put into a story is enough to make it top of mind--and thus sometimes tip of the tongue.

Leakage goes the other way, of course; the real world influences all our fiction. Why, the things I could point out in my fiction and that of many friends...but that would be telling, and you know I'd never do that.