it's strange, but. . .

. . . lots of locals have not yet internalized the Chinese diaspora (or the white or black diaspora, for that matter). Visual cues are the sole determinant of ethnicity, and ethnicity is the sole determinant of cultural identity. It is presumed that white people are from Europe or the Americas, speak English, and exist within that ethereal caste of Western power and politics under which scuttle and cower Eastern features and feet.
Prior to arriving in China, I'd always felt like a bit of a black sheep physically in Asian communities. In Taiwan, local vendors looked upon me as an American. I was too tall; my shoulders were too broad and too dark from too many swimming seasons; my hair was cut funny because I'd insisted on cutting my own hair in college. I wore the wrong clothes. Taiwanese girls, despite living in a sweltering, tropical climate, didn't wear tank-tops, didn't wear flip-flops, and definitely didn't wear college-issued running shorts.
Shanghai, however, seems to have less exposure to ABCs. They're more familiar with Europe and Europeans than Americans, and China has that whole chip on their shoulder about being at odds with the West. If your face - as mine - is Chinese, it's assumed that you are from China. If you give yourself away - as I frequently do in vernacular - it's assumed that you are from Greater China.
Cabbies can generally tell that something's a little off about my speech. It confuses them because it's not in the accent or in my ability to express and converse. One shrewd driver commented that I articulated myself perfectly (he concluded that I wasn't Korean or Japanese) but that my choice of wording was too peculiar to be local (He eventually correctly guessed that I'd be reared in a Chinese-speaking household in the States).
In any case, people rarely, if ever, guess that I'm an American. When it is revealed, they ask me if my English is any good. I clarify that I was born and raised in the States also, so yes, I'm a native English speaker. This frequently perplexes people, as they consider the apparent incongruity between my appearance with the information I've just supplied.
What Chinese people have internalized though, is the glass ceiling. Racial profiling, therefore, gives foreign visages an incredible advantage. I'm full of confidence when I'm in the company of white people; I feel invincible alongside a white man in Shanghai. (No reservations? No problem! Don't want to pay the cover? Don't have to!) Chinese people, through commitment to some obstinate pride, are embarrassed of communicating in accented English, and will readily adhere rather than attempt to argue in non-native English. I've started this dirty habit of speaking in veryfast and pronounced English when I'm not getting my way. It works like a charm; the language of oppression (sadly?) is more cogent than articulate Mandarin.