For example: I dreamt one night of a violent episode in a restaurant. The stark drama of it woke me up sharp with a jolt of fear; my fists were clenched tight, as in war status.
In the dream there was blood and carnage; loud voices and shocks.
It didn't take me very long to realize I was dreaming about an upset at work that I had not resolved. I had sailed past the event during my waking hours; but at night, dark, animated symbols arose to inform me I was still angry. This kind of information is incredibly useful; it tells us about issues that need our attention and healing. Without the dream pointing to some unemptied garbage, the anger may well have moved on to become flu. Or worse. We cannot get away from our feelings, however buried.
So dreams are a tool. Some people say they do not dream, or do not remember their dreams. If you are one of the ones who feel dream-deprived, it can be useful to encourage your dreams to announce themselves. How do you do that? Simply by telling yourself to recall your dreams before you go to sleep. Do that for a week or two, even if you feel silly doing it, and in time the message gets sent. You will start becoming conscious of your dream activity.
And lest you pooh-pooh the whole arena of dreamspace -- remember, it's another source of information (and a deep one) about you and your consciousness, about you and your life. Can you ever have too much of that?
Dreams can solve intricate problems; Einstein is just one of many scientists who reported he received answers to long-sought questions in a dream. He had a mathematical problem with no answer; he pondered it, tasted it, smelled it, dwelt with it for days and months and years. One night, the Infinite Mind we cannot fathom brought him a reply in his dreams. It made him jubilant, he said. Case closed.
Dreams can tell you where you are going, where you are going astray; what you truly want to do next, whether to stay in your job -- or not; how you feel about money, family, jobs, music and pizza, what or who is worrying you, things you don't like about yourself (and how to amend them) and why you are,when all is said and done, an absolutely glorious being. A miracle, in fact.
When a medium can give you all that, by all means: visit it.