I think there may be the makings of several coherent essays in here, and maybe someday I shall write them, but right now I'm just going to braindump.
You can either be frustrated by these kinds of conversations, or you can be amused. I choose to be amused. They come up frequently enough that this makes my life a lot more fun.
"Where are you from?"
"No, I mean where are you from?"
"I live in Boston."
"I mean where's your family from?"
"I mean what are you, like, Japanese or..."
"Mostly American. I grew up in the suburbs of Chicago."
Ok, so maybe this is stubborn immaturity on my part, but after a couple decades you learn the folks who ask these questions usually don't give you the time to explain that your genetic heritage does not necessarily represent your primary cultural identification and probably wouldn't care if you did; they just want you to Be Chinese so you fit into a nice little mental checkbox. (That having been said, I'm also proud of being Chinese-Filipino; it's just not my default mode.)
"Wait, so you can't hear."
"I can hear, just not so well."
"So how do you understand me?"
(no voice) "Can you understand me?"
"That's the first thing everyone asks, and yes."
Whenever you don't fit into a default category, you get the opportunity to make others (and yourself) aware of the assumptions people make. And sometimes - often, really - I love that. I love that I repeatedly get the chance to explain Olin (not all Boston-area engineering students went to MIT) and open source and education and all this stuff, I love that I repeatedly get to make people go "...wait, how does that work?" and maybe, just maybe, rewire the way they see the world a little. Also, if I didn't love it, I'd probably go nuts.
"You're not supposed to be able to do that."
"But I am. This is normal for me."
It's why I'm grateful I can chose to pass; sometimes it's tiring, and by choosing the universes that you want to move in, you can sometimes lift that label from yourself and move around more freely for a while, so you can go back into the Big World later. It also makes it all the more wonderful when you meet someone that already knows what you're talking about.
Stereotypes aren't bad, per se - they're efficiency tools, but like all tools, you've got to know whether they're on or off, and when and how to activate them. They're potential extra data, not gospel. And when you're repeatedly in the position of explainer, you learn which signals are triggers for what larger cascade of assumptions, and where in that mental structure lie the points you can go poke! to - it's like bringing a guy twice your weight down with a wrist lock. (Which is also fun, but which I rather suck at doing. I need to go back and learn more.)
Leverage: it's what lets you flip a lot of thinking with just a little bit of time. I do not grok this fully yet, but I understand it as something that I already do - and need to become more aware of - and then learn to use it more effectively, in any domain, at will.