Different people have completely opposite, and sometimes tangentially off the beaten path notions about such dreams.
If you actually HAVE some, however, your “opinion” is likely to change.

An average person dreams three to five times per night. Some dreams are more detailed than the other, this is due the REM and NREM stages of sleep. This is normal.
Some people just have to believe in something (not that I’m criticizing). Their beliefs help them get through the day. Dreams come in handy for such people.
Dreams could be beneficial and harmful. Say for instance, I dreamt I aced my exams and I woke up believing it, it could give me the confidence I need to stop fidgeting at the sight of the question papers. In this case it’s helpful but say I dreamt I studded my foot and in reality I ended up doing just that, I could choose to call myself clumsy and pay scrupulous attention to the road or blame the dream.
Dreams are reality. It’s not like the moment we close our eyes reality disappears and we become “unreal” and the events of our dreams don’t happen.
Waking life is reality. It is all reality. So why wouldn’t it make sense for reality to flow from one moment to the next? Even from a dream moment to a waking moment?
Perhaps you are more integrated than most. Some people keep so many secrets from themselves that these things only surface in dreams and never in waking life. Perhaps you are more in touch with the whole of your life and therefore events flow from unconscious to consciousness more fluidly for you.
Some dreams turn real because you manifested them. When you manifest something your unconscious mind starts showing you opportunities to fulfill the same. Dreams are just the gateway. If you have a strong desire to achieve something your mind will continuously find ways to reach closer to your goal.
Personally I believe dreams do come true, however in some cases, do we subconsciously make our premonitions come true?
If you dream you were at the zoo, and later someone says what do you want to do?
Would going to the zoo be a premonition, or did you subconsciously make it happen?
It’s already in your subconscious, and it constantly communicates with the conscious mind. Is that a coincidence, or is it a premonition, or do we at times, make our premonitions come true?
Or, is it all of the above?

When I was a kid, this used to happen to me a lot. It still happens from time to time, but not as much as it used to. I was skeptical that there wasn’t something else going on.
Precognition becomes understandable once we realize that time doesn’t flow: it is our consciousness that moves through time.
The usual concept of time in which the past is no longer there, the future is not yet and the present only exists is nonsensical because the present has no duration: what I said a split second ago is in the past and what I’ll say next is in the future… So where is the present? It’s just a line without thickness separating the past from the future. A line without thickness is only a concept, just like an axis (an axis is not a shaft), it is not a real thing, it doesn’t exist. Therefore, the usual way of seeing time flowing should lead to the logical conclusion that nothing exists — which is absurd!
In the dream states we all venture out of our bodies -the soul- and explore the various future dramas and probabilities. In the dream state we work out reality before it happens.
Dreams are mental work and play combined, psychic and emotional reach creative dramas. They also involve you in the most productive of enterprises as you begin to play with versions of events that are being considered for physical actualization, as on personal level you “view” the probable events which you family, organization, community and country will actualized.
In conclusion, I say your dreams only motivate you to do whatever it is you do. Our beliefs could build or ruin us.