You know you're from the DC Metro area if….
You say you're "from DC", but you actually live in Maryland or Virginia … it's just simpler that way.
Your distant relatives (some of whom you haven't met since your first birthday) call you for someplace to stay for free when they visit Washington. If you haven't yet gotten used to saying "no" they might … might … take you out for a fancy dinner at IHOP. When they ask if you'd like that, you try to explain the wonders of Salvadorean, Ethiopian, Afghan, Thai and Indian food but eventually you give up and go to IHOP.
You listen with a smile as they rave about their visit to the Air and Space Museum, but you know several that are much better. Likewise, they don't understand why you're not thrilled to join them visiting all of the monuments. You have never actually been on the White House tour or to the Washington Monument (MUCH too much trouble). When you say you're going to the Mall you might mean you're going shopping, but you probably mean you're going to a museum.
You know nobody who smokes. This mystifies your out-of-town guests.
You live in Virginia, but it's Northern Virginia … it's nothing like the rest of Virginia. The rest of Virginia doesn't like us and they don't vote for anything we favor. And we don't have southern accents! (Exception: When you went to college somewhere else and asked "what are y'all doing?" they laughed at you for saying "y'all".)
You know instantly who lives here and who doesn't. The people who live here, young and old, all have photo IDs on lanyards around their necks. The tourists have matching neon shirts and caps and they all shop (filled with wonder) at Pentagon City Mall. Eventually, you find yourself uttering the phrase "damn tourists" entirely too often.
You know where Vietnam is - it's been re-located to the Eden Center in Falls Church. Most of Korea is now in Annandale. Nobody is left in Bolivia or Ecuador, but you can find them all on the soccer fields of Arlington on Saturdays and Sundays. In off-hours and basement rooms, your church hosts Korean, Vietnamese, Hispanic and Ethiopian congregations.
You not only know what the World Bank, the IMF and EPA are, you know WHERE they are (and where the FBI and the CIA and the Pentagon are). You actually know someone who works for the CIA. Some of your friends don't know what their parents/spouses do (it's secret). You know several Congressmen/Senators/diplomats because they're your next-door neighbors. You can live next door to an "unindicted co-conspirator" and not worry for your safety on that account — for that matter, your kids probably play with his kids and that doesn't bother you either.
You know that fancy stretch limousines never contain anybody of the least importance. Really important people are driven in quiet black Lincoln Town Cars with reading lamps on the back of the rear seat. They are often seen empty (drivers chatting in a bunch nearby) next to television satellite-uplink trucks (gotta get that speech onto the evening news).
The sight of armed security no longer bothers you. The sight of LOTS of armed security at the Pentagon Metro station doesn't bother you much, except for the thought that they're looking at you and considering whether they might need to shoot you.
When people ask for directions, you tell them it's either "inside" or "outside" the beltway. It is ALWAYS rush hour. You think traffic moving 1 mile in 5 minutes is "not that bad." You actually know at what times the streets change directions and which direction they change to. You know that in Arlington, the same road can run parallel to itself, and often changes names mid-block.
You can take the subway to another state.
It is (and will always be) "NATIONAL AIRPORT" not "Reagan National”.
There are at least four 7-11’s on your road, about ¼ mile apart. Next to each is a McDonald's.
You turn on the "local news" to hear about the latest national scandals/events.
The parking lot at work looks like an auto importer's showroom.
You laugh every time you see the "Surrender Dorothy" regularly obliterated and then re-painted on the bridge over the beltway approaching the Mormon Temple.
You can go to school or work every day and see at least 5 people you've never seen before. The same number of people have suddenly moved away.