I am a big fan of science fiction and have been for almost twenty years,
but one thing that usually bothers me in science fiction is that even
when describing societies in faraway future the "mainstream" science
fiction novel, tv series or movie supposes that nothing much changes,
and if something changes, then the model for this new kind of society
is taken from Earth´s history, and usually not real history, but from
`popularized´history, which I mean the kind historical knowledge that
an ordinary person has a decade or several decades after their
education has ended. So we end having space empires ruled by
emperors and aristocrats, or like in `Firefly´, the victorious North and
the defeated South, played again in space.

Of course it can be said that science fiction is, like all literature, about this
day. But the `today´that the work is `commenting´ could be hidden
better. And the authors could let their imagination float more freely;
in science fiction tv series and movies the most common alien is the´
"human with a badly-masked face", but even in good sf, like Iain (M.)
Banks´s `Culture´ we find that pretty much the same human type has evolved on a huge number of planets, which I find a pretty... unbelievable.
I have to admit, that an alien civilization or entity, who stays always
a mystery is a better thing that an alien civilization that is practically
`us, but little different´.

And then there are those alien planets in tv series and movies that
are all, so it seems, exactly like California countryside.