Why do some people have lucid dreams while others don't?

Lucid dreams represent a mistake in the mind - rather like a hiccup - that confuses aspects of awakening with aspects of deep sleep. Instead of the conscious mind being at rest while the unconscious mind produces dreams, when lucid dreams occur, some portion of the mind becomes conscious and aware of a dream taking place. Some individuals experience lucid dreams naturally or with very little effort, while other individuals cannot achieve lucidity while dreaming no matter how hard they try. This is nothing more than natural variation among individuals, similar to the ability to roll the tongue or whistle between the teeth. Neither variation has particular value or significance.