If I'm dreaming and see myself with extra fingers, then I'd probably think: "Yeah, they're that way because the cat granted me a boon of cursed pancake syrup."
Just though I'd let you know,when you do start lucid dreaming,you risk having sleep paralyzation, in which you wake up,cannot move,and you hallucinate,and believe it's all real.Very scary.
I lucid dream about a third or so of all my dreams, and nearly two thirds of my nightmares. The nightmares are the best, because you're being chased by a serial killer, you suddenly realize that you're in a dream, and you develop Liam Neeson Badass Skills and kick the killer's ass.
When you are lucid dreaming, you are also closer to your inert self. So you can ask yourself really personal questions that only your subconscient know. It's a really fun thing to do.
Well when you're awake, every tought you have is filtered by your logic, your image of yourself, your judgements, etc. But when you're asleep the part of your brain that does that is also asleep. So you can basically ask anything you want, because chances are that you think you know the answer and you think you know yourself, but you don't.
Although, come to think about it, there have been a couple recorded instances of shared dreams...