Losing your dice bag would be a serious financial blow.
You've been gaming for more than half of your life.
You own your own weight in gaming books.
You took geology, sociology, psychology, kendo, archery and horseback riding in college, so you could build a realistic game world.
You keep having dreams where you are your character...and you think it is neat, rather than consulting a professional.
All your cannon-fodder NPC's are named after people who have ticked you off at work.
You have a heated debate about how your paladin could beat the alien in Predator 2.
You have a heated debate about how your mage could beat the paladin that could beat the alien in Predator 2.
You actually know the name of the Predator species (Yautja).
You could paper your bathroom in character sheets.
You could paper your bathroom in different versions of just ONE character.
You are unable to walk past the latest game supplement without leafing through it, even though you know it's going to be bad.
You have more entertaining "No-shit,-there-I-was-in-a-game" stories than you have anecdotes about your family.
You talk about your characters as if they are real people.
You alternate between referring to your characters in the first and the third person... and none of your friends gets confused.
You've ever spent a significant fraction of your life modifying game rules that you didn't like... and, as soon as the system worked to your satisfaction, discarded it.
You've ever seen the old Dungeons & Dragons TV series.
You keep old characters around just in case someone might run that system again (never mind that it's TS:SI).
You knew what was meant by TS:SI.
You have a Ph.D. in manipulating point systems to the best effect, even though you failed high school geometry.
You're still reading this list.
You can consume your body weight in junk food in one gaming session.
You consider Altoids, ranch-flavored Doritos, Oreos, Coca-Cola and pepperoni & onion pizza a balanced diet (or even an acceptable combination).
You have been known to drive to far away places where you paid enormous amounts of money for the privilege of sleeping on floors, eating crap, buying little pewter statues of Gandalf, and meeting dozens of psychopathic members of the alternate (or similar) sex who will follow you around for months, merely for the pleasure of playing with gamers you don't know in small enclosed spaces permeated with the smell of sweat...and then signed up en masse with all of your friends to play in games with gamemasters who you've known since high school.
The owners of local hobby stores take your checks without ID because they know where you live.
You have a random NPC generator, written in BASIC, designed to run on the Trash-80 or the Commodore 64.
You've ever designed your own character sheets.
You can be more than three NPCs at the same time without generating more than reasonable confusion in your players.
You've ever discovered that you like your significant other's character better than you like your significant other.
You've discovered that spare dice make good beanbag filler.
You knew that that last question was a ringer -- who has more dice than they can use?
You've been known to have in-depth conversations about the relative merits of Champions, Villains & Vigilantes, Marvel, and DC Heroes ... ignoring the fact that all superhero systems are intrinsically sucky.
You like one of the above systems enough that you yelped when they were called "sucky."
You've thought of four or five additions to this list.
You actually wear that little ankh that comes in the Vampire Live-Action box... in everyday life.
You've actually paid to have custom fangs made.
You wear these fangs in everyday life (not to mention Renaissance festivals).
You saw "Kindred: The Embraced" and kept yelling they got it all wrong.
You have a dozen wishes in mind for when you come across a magic lamp.
You've bought a game even though you didn't like the genre or the rules, so that you could fix the rules and convert them to a different genre.
Your most important criteria for a mate is that they're a gamer, too.
You remember when all games referred to characters as "he."
You take notes from books for character histories.
You've written character histories that are longer than most novels.
You've ever argued against a combat rule based on your experience in the SCA, the military, or the police; or because of your degree in medieval history.
You watch war documentaries with GURPS Vehicles so you can tell how much damage the 4-inch naval gun using an APX shell does.
You collect building plans to use as site maps for games.
You have examples of weapons from your games in the house -- "so the players can't argue about how heavy/long/clumsy/etc. they are...."
You buy CDs of specific music (or sounds) just to use as background atmosphere for gaming.
You've ever found yourself associating with people who you'd otherwise avoid in public - because they were gamers.
You have a place where the paraphernalia of your gaming youth is displayed for the curious as a sort of shrine to "the good old days."
You have three or more dice-boxes (one in use, the others retired, holding seldom-used, antique, or faithful) dice, or doing duty on the Gaming Shrine.
You tried gaming outside, for that "natural, woodland atmosphere." Ahhh...until you found out the hard way about the @%#*! WIND, when it blew all of your maps/character sheets away.
You're STILL reading this list!
You've ever spent more time in a single gaming session than a Jerry Lewis Marathon... and you do this regularly.
You feel guilty if you have more than one character at a time.
Your character gets more mail than you do.
Trekkies look down their noses at you.
You've actually played an RPG online.
You compulsively mail or ship things to people (sometimes at great expense) because whatever it is reminds you of their character.
You STILL watch Excalibur every time it comes on.
You've ever seen the solid brass d6s ... and HAD to have them so that they made more noise than everyone else's when you rolled them.
You think to yourself upon seeing d100 ... why not just use percentile dice?
You've said "roll initiative" more times than you've sung your country's national anthem.