For me, I tend to be much more conscious of myself when I'm writing than when I'm doing other creative activities. I consciously think, "Okay, so now these people have to meet and do so-and-so," and "Somehow I need to get this guy here, so let me have him travel for so-and-so reason," and, yes, "It serves as a symbolic reminder of the doctrine of..." and so on. Sure, I do sometimes get surprises from my characters - one night a character suddenly revealed something quite shocking about himself to me, and then I couldn't sleep.

But generally I'm quite aware of myself and feel pretty separate from my characters, even if I love them!
On the other hand, when I world-build, I just...I don't know. It just happens. Like with the languages I make up - I get a kernel of an idea about how some grammatical structure might work, and then it rolls around in my head for a while and picks up bits of ideas that are scattered around in there, and then eventually I get a sense of the
feeling of the language - its personality, its essence. And then actually working out is pretty easy, because I know somehow what should be in it. I
know it should have animate/inanimate gender, and it shouldn't have case, and it should put adjectives after nouns, and it shouldn't be ergative. The details, like what exactly constitutes animate/inanimate gender (I always get stuck on body parts, for instance), can sometimes be tricky. But I know what the general structure of the language should look like. Same with my imaginary countries, or historical characters - I get the feeling of what they are or who they are, and then everything just flows.
I wonder if that's because my writing is meant for other people to read, while my worldbuilding is really for myself alone...and so I want my writing to be well thought-out and carefully structured so it's enjoyable to others. But my worlds are just for me, and so as long as I enjoy them, it doesn't matter if they make no sense or are horribly cliched or whatever it is...
Roager the Ogre wrote:
One of my favorite things about writing is the moment when one of your characters surprises you. You do all this planning, you add all this detail, you create their background and think you know everything there is about them when all of a sudden they do or say something that catches you off guard. They reveal a detail you've never thought of before and it turns out to be better than anything you could've planned.
Yup. That's exactly it. It is a lovely feeling. The funny thing is that I also get it when creating languages - I suddenly have the most brilliant idea about how some grammatical structure can work, and then I have to chuck all the pretty conjugation charts I made of the old boring structure...
Caeli wrote:
I am constantly frustrated that my characters never have the courage to show up on paper like they run around in my head.
Too true! It's also frustrating for me that when I'm...well, my sister and I call it playing pretending games, but it sounds more cool if you call it, say, live-action role-playing, or improv theater...well, when we're making up a story together and acting it out, our characters usually really come alive. But then I sit down and try to write a story and the characters talk like example sentences out of the dictionary. Sigh.
Blayne B. Trent wrote:
And all (except few) my characters hair and eye color somehow seem to change after very paragraph. Finalizing physical description is one of the last things I do. =)
Haha, I'm the same, usually

I am really not a visual person - I have a horrible visual memory and my dreams are never very vivid - and so I never imagine how my characters look in much depth. Now and then I'll hit on a detail - say, somebody has freckles, or messy blonde hair. But generally I'm horrible at coming up with my characters' appearances. So I try to use characteristic mannerisms and so on to describe them instead...as much as I can!