never judge a book by its cover

A couple Caucasian friends were telling me the other day that they sometimes speak in English about the people around them because they don't expect to be understood. So they'll laugh about the taxi driver's singing while riding in the cab or comment about the clothes of the person walking two feet in front of them. I mentioned that that wouldn't go over very well if they were around somebody like me who looks Chinese but speaks native English and would probably make some brusque, sarcastic comment in English to bust their cover.
Turns out, I had quite the opposite experience in a cab this morning. I was running late and was having difficulty grabbing a taxi to get me to work on time. Next to me, I saw a man look urgently down the street, mutter "Scheiße" to somebody near him, and then walk off. Apparently the German was having just as little luck finding a cab.
A few minutes later, I managed to hail one down. As we passed the corner, I saw the German guy standing with two other European men, all trying to hail down my taxi. The taxi driver laughingly waved them away and then turned to me.
"San ge lao wai. Yi ge de guo ren, yi ge fa guo ren, yi ge yi da li ren." Three 'old foreigners'. One German, one Frenchman, and one Italian. (How could he tell?) "To us, they all look pretty much the same," the taxi driver quipped, "And to them, so do we! A lot of foreigners are moving to Shanghai now. Yes, now they like to live here, and they always say, 'Your country is so cheap!'" He slapped his knee in amusement, and I grinned from the backseat. I didn't want to embarrass him, so I was silent for the rest of the trip - lest he recognize my accent and realize that I was a "lao wai", too.