We don’t control most of our dreams just because we got used to the law of physical world and from force of habit we act with regard of our usual life in awaken state. If you learn how to think differently, accepting that in other dimensions the laws are different, you can multiply your abilities and opportunities. Other world has other laws. Other dimension opens other opportunities.
Any sentiments, including your emotions, haunting thoughts and absorbing feelings from love to hate and fear (especially fear!) at once reveal themselves in astral and mental planes. Consequently, we see all these peaks and changes in our dreams. The most important that we see not only those we know about but also those which happened with other people or will happen in the future!
The stronger are feelings and the more haunting are thoughts, the brighter are images in our dreams. What, putting it plainly, are the major contents of our inner world? Our own thoughts, ideas and feelings. That is why our consciousness is most active on planes where they are free to act on their own, restoring worlds and universes.