Belief sloshes around in the firmament like lumps of clay spiralling into a potter's wheel. That's how gods get created, for example. They clearly must be created by their own believers, because a brief resume of the lives of most gods suggests that their origins certainly couldn't be divine. They tend to do exactly the things people would do if only they could, especially when it comes to nymphs, golden showers, and the smiting of your enemies.