I think dreams may serve multiple purposes. Partly, as I understand it, they are a by-product of the brain sorting memories, and possibly discarding detail, or extraneous data, which no doubt influences the bizarre juxtapositions we see in dreams. But I also think they are sometimes a window into what is going on in our lives. The images in our dreams are composed of images we already have stored somewhere in memory; however strange, there's nothing in a dream which isn't already in our brain.

Tarot cards appear, uncannily at times, to work because in essence, the multiple symbols on each card automate cold reading for the reader. A superstition around Tarot is that you should not try to read your own cards. I think there is a little bit of reason there, because you will certainly be best at cold reading yourself.

Some dreams, IMO, act as a Tarot deck, and are all the more powerful because the symbols dreams contain are all our own - on some level we understand their personal significance. So when something significant is happening in our lives, even if we are not yet consciously aware of it, we may read the symbols contained in a remembered dream and come to a conclusion that subsequently proves true. I don't think the dream itself is prophetic, or that the unconscious mind communicates directly through dream imagery, but that information is already there, and we choose which dream images will suit our meaning. This can be very beneficial sometimes, I believe - it has been for me.

Here is someone else's dream, that maybe illustrates the above. This woman's young teenage daughter became ill, and after a couple days, the mother took her to a doctor, who diagnosed a common flu. The daughter became more ill. The mother took her to the emergency clinic at the hospital, and again the diagnosis was flu. The daughter had a collection of symptoms which should have been seen, but weren't. Her belly was distended and hard, her eyes were sunken and dark underneath, her breath was dreadful. But the mother was very trusting of doctors.

That night the mother dreamed that she woke, and on the bed was a mummified leg. In horror she ran through her house, finding desiccated body parts in every room, and the scent of carrion was everywhere.

When she really woke, she took her daughter back to the hospital, and refused to leave. By then, the daughter's symptoms were very obvious - she had a ruptured appendix and was dying of peritonitis and dehydration. A very good surgeon saved the girl, and the mother credits the dream to God's warning. I think she saw and on some level understood her daughter's symptoms, and plucked the dream images to remember which were in agreement with her knowledge.