you know you're a TCK when...

"A third culture kid is a person who has spent a significant part of his or her developmental years outside their parents’ culture."
TCKid.com

"Third-culture kids are those who have spent some of their growing up years in a foreign country and experience a sense of not belonging to their passport country when they return to it. In adapting to life in a 'foreign' country they have also missed learning ways of their homeland and feel most at home in the 'third-culture' which they have created. Little understood by American schools, where they are often considered an oddity, what third culture kids want most is to be accepted as the individuals they are."
US Dept. of State

You know you're a TCK when...

• "Where are you from?" has more than one reasonable answer.
• You’ve said that you’re from foreign country X, and (if you live in America) your audience has asked you which US state X is in.
• You flew before you could walk.
• You speak two languages, but can’t spell in either.
• You feel odd being in the ethnic majority.
• You have three passports.
• You have a passport but no driver’s license.
• You go into culture shock upon returning to your “home” country.
• Your life story uses the phrase “Then we moved to…” three (or four, or five…) times.
• You wince when people mispronounce foreign words.
• You don’t know whether to write the date as day/month/year, month/day/year, or some variation thereof.
• The best word for something is the word you learned first, regardless of the language.
• You get confused because US money isn’t color-coded.
• You think VISA is a document that’s stamped in your passport, not a plastic card you carry in your wallet.
• You own personal appliances with 3 types of plugs, know the difference between 110 and 220 volts, 50 and 60 cycle current, and realize that a trasnsformer isn’t always enough to make your appliances work.
• You fried a number of appliances during the learning process.
• You think the Pledge of Allegiance might possibly begin with “Four-score and seven years ago….”
• Half of your phone calls are unintelligible to those around you.
• You believe vehemently that football is played with a round, spotted ball.
• You consider a city 500 miles away “very close.”
• You get homesick reading National Geographic.
• You cruise the Internet looking for fonts that can support foreign alphabets.
• You think in the metric system and Celsius.
• You may have learned to think in feet and miles as well, after a few years of living (and driving) in the US. (But not Fahrenheit. You will *never* learn to think in Fahrenheit).
• You haggle with the checkout clerk for a lower price.
• Your minor is a foreign language you already speak.
• When asked a question in a certain language, you’ve absentmindedly respond in a different one.
• You miss the subtitles when you see the latest movie.
• You’ve gotten out of school because of monsoons, bomb threats, and/or popular demonstrations.
• You speak with authority on the subject of airline travel.
• You have frequent flyer accounts on multiple airlines and constantly want to use said frequent flyer accounts to travel to new places.
• You know how to pack.
• You have the urge to move to a new country every couple of years.
• The thought of sending your (hypothetical) kids to public school scares you, while the thought of letting them fly alone doesn’t at all.
• You think that high school reunions are all but impossible.
• You have friends from 29 different countries and sort these friends by continent.
• You have a time zone map next to your telephone.
• You realize what a small world it is, after all.

Those in bold I've most certainly experienced/thought/felt at some point in my life, especially during the first year I lived at "home" full-time.