lucid dreams for me seem to be more shocking, and there are more details that you notice. I haven't had that many yet but so far in my experience they're very vivid, because you're conscious enough to absorb what's happening in your surroundings. For me, dreams are hazy because you don't pay that much attention to everything around you; most people have a tendency to do that in real life too. Just about everything carries over into dreams. One dream I had involved wind brushing against my face; I remember distinctly feeling that, and generally I can only remember images and maaaybe some dialogue. It's the surprising amount of realism and your ability to "look around" a little bit that make them more memorable, to me anyway.