You Know You Write Sci-Fi If...

...your characters are always trying to figure out how to clobber the enemy and achieve their objective without punching holes in a hull and getting sucked out into space.

...speaking at least three languages that didn't originate on your home planet is a social necessity.

(I always love reading this thread in all the genre forums, but I didn't see one in Sci-Fi yet. Feel free to flog me if I just missed an existing thread!)

You have to plan for the eventuality that someone my a rip a hole is space and time, causing the collapse of civilization as we know it and/or allowing inter-dimensional beings to escape and take over your planet.

... inanimate objects inspire you to write a new character.

...your vocabulary words begin with "tri" or "di" and end with "lithic" or "ode"...
...race is more than a social issue...
...your character uses a towel, screwdriver, or other household object in an extraordinary way to get out of sticky situations...

...you develop a new alien race after 20 minutes of messing around with a video game (BP if said game is the Sims or something very similar).
...your characters consider riding hoover-boards to be "old fashioned".

...you create an alien language just so that you can insult people to their faces.

...you spend a lot of time trying to figure out how something very impossible might feasibly work.

...when your car breaks down, you assume it's the power couplers.

On the family calendar next to grocery list is written the formula for when light (c) will orbit a black hole. Because of course, it might come in handy.

Getting characters from point A to point B requires violating at least one law of physics.

You use a dating system that's either 'post apocalypse' or 'post migration'

You stare at the stars in the evening and try to work out which one it is that your aliens live nearby

Your page is covered in red squiggles because Word doesn't recognise the Hagneratherons of Echypilxok 8.

-You're trying to decipher a paper about the star system 55 Cancri so you know what sort of planet your characters plan on colonizing, and therefore what sort of environment they're gearing their eugenics program towards.

-Travelling at sub-light speeds is a deliberate choice rather than a fact of life

-Factoring in gravity or lack thereof is a serious consideration

- your characters name themselves, but you spend five hours trying to find the perfect name for a planet

- or a spaceship

...your character spends more time talking to computers than people

...your character pulls out a ridiculously pimped out weapon that shocks everyon around them.

...you've ever asked the clerks at the grocery store where they keep their inorganic produce.

Your primary sources of story premises are Scientific American, Science News, Nature, ....

You know right where your old college physics textbook is because you refer to it frequently.

You know a Dyson Sphere isn't the thing the vacuum cleaner rolls around on.

...Your god looks (and quite possibly sounds) a lot like Carl Sagan.

Kurzweil thinks your plot synopsis is a legitimate plan for the future of humanity.

...you have to edit your work every so often to change how you refer to Pluto

...your most descriptive passages are waxing philosophical while staring at a planet from orbit