The Future, no one knows, its all subjective to a certain extent, we can predict with a high level of accuracy but not definate. Some say it'll go for the best, we'll be on holidaying on far off planets such as in star Trek, others are predicting a Mad Max future where law and order has broken down, fossil fuels have all be used up, a bleak future in other words.
A Future Positive is a future where our technology has improved to a certain extent where life is as near to perfect as possible. We will have unlimited amounts of energy, we can travelled further into space, have defeated disease and maybe even met an alien form. One day we may find a way of breaking Einsteins laws that prevents us from travelling to far off and distant planets but until then we'll be stuck on this planet hoping for a future that will bring peace and prosperity.
We may make it to Mars, terraform it and live there which would be the answers to our overpopulation problem on Earth. We may finally get in contact with friendly aliens.
Examples of films and television of future positive are :-
A Future Negative is where the technology has not progressed enough or has progressed too much to an extent that it has become a threat. The fuel for our energy generators has run out leaving us to use wood for burning in the extreme case, diseases that were once combated by vaccination or anti-biotics have become immune to our defences and space on the planet is at a premium either through global warming or too many people. One day all life on this planet will be extinguished but that won't happen for at least a billion years so no need to worry. In that time, there's no guarantee that life won't have already been wiped out.
In all likelihood, we'll be stuck on this planet for the rest of humanities life, some lucky few may make it to Mars but for the vast majority will be stuck on Earth. In the most unlikely situation, we may make contact with an alien race who turn out to be hostile.
Example of films and television of future negative are :- Judge Dredd, Logans Run, Terminator , Waterworld