Presuming that if your writing you are not going to change human nature, any writer needs to understand that certain characteristics are not going to change. Even though they may be bad or hurt us they are a part of who we are as a species and must therefore be taken into account.
This may seam obvious but there are some shows and books that posit that money will not exist in the future.
I don’t buy it. I could buy that we would reach a point where anything that is a basic need would be taken care of for free, medical care, food ect. I could see that money would just be for luxuries, not for necessities but I can’t image a world without it altogether.
Humans tend to work best when they are working for a personal goal. Few people would keep their current jobs if they were told they would not be paid for their work. They also might do a much worse job. For example, if your making a movie just for yourself you would make it much differently, then if you were making it for a wide audience that it had to appeal to.
Violence and crime
I hate to say it but both violence and crime will remain with us, there are any number of things that could reduce both but nothing that will eliminate them.
At the minimum there are people who would rather just steal then work for a living. There are many things that could reduce it but nothing that would stop it.
This is one that kind of bugs me, many people see religion as a irrational part of the human psyche that we will be able to shed at some point in the future. In so doing it would ease a lot of suffering.
The concept of a supreme being or beings have been with us for as long as there have been humans. Which religions will change, and the number who believe in them will change however I believe we will have religion for as long as there is a human race.
The exact reasons for religions are very much up to debate but if history has shown us anything, it is that they are here to stay. That being the case if you are making a future society you have to take religion into account.
This might seam a bit obvious but one thing that some writers forget is that disagreement is not just about facts. It is very possible for two people to have identical facts, understand each other’s logic perfectly and still disagree.
As a rule everything anyone believes will have someone else who disagrees, no matter how logical or clear. You can just say “X was proven” and say that everyone accepts it, however that is not how humans work.
When I read something like that in a book, where an entire people believe something and no one disagrees I assume some form of coercion is going on.
There are people today in the US who believe the earth is flat, we never landed on the moon and even that we should go back to a monarchy.
Sex is one of the major driving forces of the human race. If you have a character interacting with someone who he is attracted to it changes the dynamic even if the interaction itself has nothing to do with sex.
One mistake some writers make is in thinking that a egalitarian culture means that people ignore sex, that it no longer effects our behavior. That simply is not the case.