I think there can be occasions when you could become too conscious in a LD. If you are amazed when you become lucid and begin to question the dream images, or try to rationalize the dream content, you can easily become too aware of reality and wake yourself up. Over the years, I've found that when I accept the imagery without worrying about how I am perceiving it or where it is coming from, lucidity will be much longer than mere seconds. I guess it would be easier to say that you might need to be calm and "go with the flow" with lucidity, especially if you are just beginning to LD.