1. ...You changed time zones three times in two days.
2. ...One day you drove on the right and the next day you drove on the left.
3. ...You conducted business in four different languages in two days.
4. ...You spent the time on the ferry between Spain and England applying for visas to Russia and China.
5. ...You got confused by all the visa stamps in your passport and had to recount them several times to make sure you didn't overlook any.
6. ...You emptied all the euros out of your pocket and stashed them in your car's console, while simultaneously snatching up all the pounds and pence (and filtering out several other currencies) to fill the void in your pocket.
7. ...You have a system for showing your passports to border officers.
8. ...You considered it a personal victory that your third crossing of the English Channel in the last five months did not result in any puking.
9. ...You stopped for groceries and were thrilled to discover a photo booth where you could have visa photos made.
10. ...Your children often begin sentences in this way: "On our next trip around the world..."