Sometimes it can be a dream in which you are mentally awake and have full recollection of going to sleep, mental presence and full control of the dream state, sometimes just a dream about the subject of lucid dreaming that often ends in a digression or false awakening. Sometimes I've had dreams where my thoughts are separate from the dream character I am acting as, like when watching a film. It doesn't occur to me then to affect events in such a case, since I'm kind of a passive observer even though I'm aware I'm witnessing a dream. Lucidity doesn't automatically guarantee full mental awareness, or dream control.