My Perception
Most people believe their thoughts can in no way influence the present anywhere else in the world (at the exact same time) much less the future or past. Your consciousness (the conjunction of the brain and thinking process) is basically the catalyst for creation. Don't discredit your ability to a higher power or intelligent design. All thoughts move instantaneously, meaning time does not affect them therefore the thoughts have no concept of past present or future. The closer mass moves to the speed of light the less of an effect time has on it, for example the photons that make up light today are the exact same age now as they were when the universe was created. What this has to do with your dreams is that when you apply something that is not limited to time and affects everything around it at all moments then you have what we perceive as the present and future. This is just a fancy way of saying you help shape yours and others environment. I say helped because since there are billions of thinking minds that your consciousness, with others, helped to create situations for that to happen. Although not working together most of the time. I know this sounds far fetched but hey so is the dilemma. Well that is just my point of view and really doesn't mean anything unless you share the same meaning in life.Christianity
"If a man's gift is prophesying, let him use it in proportion to his faith. If it is serving, let him serve; if it is teaching, let him teach; if it is encouraging, let him encourage; if it is contributing to the needs of others, let him give generously; if it is leadership, let him govern diligently; if it is showing mercy, let him do it cheerfully." Roman 12:6-8 NIV
We all have received a gift from God and when you find out your gift share it with the world in order to encourage those around that all is not lost. Go and comfort those who might have gone astray from the path of righteousness. Help them to realize their own gift as well as the blessing of eternal life at the side of the father. Everything has a purpose and it is up to you to find that purpose. A blind man cannot see but can hear better than the man who cannot hear but can see great, these differences in us help us to depend on each other so we can form together and become family as Christ wants for us.
Science
First off there are no hard facts stating why we dream and why it pertains to certain topics. Throughout every single day your subconscious mind picks up on hundreds of thousands of tidbits of information stores them and continues. Your thoughts tries to make sense of that information to corelate into thoughts. When you are actually asleep most of your body becomes dormant while the mind speeds up and processes the information that weighs most on your mind, like when you are stressing over a test and then you have a nightmare about getting kicked out of school. When the precognitive comes into play is normally your subconscious processing information at an increasingly faster rate than your conscious can or cares to process, so it notices signs that you would never have known. Of course in order to be rational it has to form a conclusion. This does not mean your dreams can tell you everything that is going to or will happen, it is merely an attempt to make sense of information that it has gathered though out the day, or even past days. These dreams become stronger over time when you unknowingly gather more info about a similar topic. Even when you read or see something you don't always store it in your long term memory, so sometimes it is more obvious than you give credit, for example when you read the paper in the morning you are gathering allot of data and you will not remember all of it because you do allot of scanning, skimming and browsing (kinda like your subconscious) so that vital info that will help predict a later event will be stored and relived in your dreams after gaining sufficient data. This explains why most of the time your dreams make no sense, one second you are reliving a childhood memory with someone who was not even in your childhood ( that's your subconscious relating that person to someone who reminds you of him/her when you were young) then you are surrounded by zombies who look like your ex and your on the moon, zombies could be from a movie you watched a few days ago and you just finished the biography of Neil Armstrong and you were reading to get over the stress of your breakup. So sometimes it can make no sense like that rant or could be more obvious. Any way your brain tries to make sense of the world.