I don't know all the technical or biological details, I just know that when I realise I'm dreaming, I can take control and do stuff like flying and it feels just like real flying (or how I'd imagine it to feel, I guess). It's a complete rush. Maybe you haven't had a proper lucid dream? It's definitely nothing like just closing your eyes and imagining. Everything just feels real, like it does in a dream. So real that even in a lucid dream I find my self questioning if it is in fact a dream or real.

Each to their own. I've had some pretty amazing vivid lucid dreams.

It's actually much harder to play pac-man with an 8-way stick.

Now if they only did Saga of the Exiles, I'd be interested.