In non-lucid dreams I have some kind of control, in the way that if something I don't like happens, something changes and the dream goes on more pleasantly. For example, I really fucking hate bugs, and in a dream someone had a collection of butterflies, I wished he would take them apart from me, and he hid them under a bed and I never saw them again during the dream. In other dream, I lost a train, and a few seconds after another train arrived and took me to my destination. But I have never changed something by will, it's more like my dream detects if I don't like something and changes it without me doing or noticing anything.