Today I'm going to flip that around:
You're telling people things without realizing it.
Look at it from an alien language perspective. Just using our language implies that we identify objects as separate from one another, able to be acted upon by subjects in particular ways. If you read our language it becomes evident how we categorize things - what we lump into which baskets.
Then look at it from a story-writing perspective. The things you know are slipping into your narrative. When those are things about your world and your characters, it's great! It means you're transmitting critical information below the radar, hiding it in plain sight (here's my article on hiding information in plain sight). However, sometimes things we know about our own world - the writer's world - can slip in too, and then it's not so good.
When you work in any fantasy or science fictional world - at the short story length or the novel length - it's vital to spend some time thinking through the underpinnings of your story.
Question your assumptions. Even the really basic stuff.
So what are your assumptions? That's a harder question than it looks like - because they're assumptions, they're hiding in your head.
Hard science fiction writers would probably be swift to point out that you need to know whether there's gravity, whether the air is breathable, what the sun, or suns, look like, etc. Someone on the Analog forum mentioned that if the Pandoran atmosphere is poisonous to humans, then their skin would have to be protected from it as well, so face masks wouldn't really do the trick. I'm not the expert on this topic, personally, so I'm not sure if the Avatar folks had a particular idea for what was in their atmosphere which would mean re-breathers would work perfectly - but I thought it was an interesting observation.
There's more to it than just chemistry and physics, though.
I'm revising an Allied Systems story at the moment. For me, making up an alien species, creating their language and culture, and writing in their point of view is in some ways easier than writing about the humans in the story. Crazy, I know. But here's the thing: if you put it in comedy terms, the humans of the Allied Systems are the "straight man" and the aliens are the flamboyant comedians. Not that it's intended to be comedy, but I think you see my point. It's an issue I mentioned in my post on focus: the complexity of the aliens is such that I want the humans to be easy. They form the relatively neutral background upon which the aliens stand out. This is why they often come across as kind of retro.
The hazard of having retro humans, for me, is that the Star Trek model starts creeping in my head. I don't suppose this is so unusual. Our assumptions are built up from our experiences. People in the 1950's would make assumptions about aliens based on their experiences, and come up with The War of the Worlds, or classic pulp sci fi, if they didn't model their ideas on the Cold War. They would expect aliens either to make war or experiment on them, and certainly expect the end of the world as they knew it. My experience with space and aliens comes from Star Trek (TNG, mostly), so I get that set of assumptions. Not with my aliens, since I intentionally break the expectations there, but with my humans.
So there I was, looking at my story, and I realized I hadn't defeated the Star Trek default assumption that everybody out there has a spaceship. If you live in the Star Trek universe, you expect aliens to make war, to have funny powers or rules, or to make friends - but any way it works out, you're not particularly surprised to meet them.
This is where you see the biggest influence on the story: in human reactions to what is happening. I just about hit myself in the head when I realized that the humans were way too calm about the idea of encountering spacefaring aliens. Sure, the Allied Systems have lots of aliens, but humans are one of only two spacefaring races. Which means that encountering a third one is a BIG DEAL.Take a moment to look at what you're writing, and give some attention to how your characters react to the events that occur. Think about their expectations.
Do they expect everyone to be able to do magic? Or just one person, or a few? That will influence their reaction to magical occurrences and for example, what kind of guesses they might make when faced with unexplained magical happenings.
Do they expect to be treated fairly by the people around them? If they're members of a socially lower group, they probably don't. But here's the trap: if bad treatment is normal to them, they probably don't question it nearly as much as we would. They wouldn't take offense at every little thing, and most probably wouldn't even spare much thought for revolution, which would seem dangerous and impractical anyway.
What do they expect to be able to accomplish using scientific and technological means? What do they expect others to be able to accomplish? If they've seen a lot of different technology levels, they'll tend to take surprises more in stride. If they haven't, their reactions will be completely different.
So question your assumptions before you call it your final draft. It will go a long way toward having your characters' behavior seem well-grounded, and helping their reactions not to ring false.
It's something to think about.