LD's can be as vivid and realistic as waking life and thats why we do reality checks, to bring us back from our dream into lucidity so that we can control the direction of the dream.

I have had the trifecta, one after the other, Dreamed, became lucid, opened my eyes and saw reality (whilst still asleep, although I could not move my eyes, SP) back to dream, lucidity etc.
Now that was an experience....