Midwesterners are self-effacing. We are not brash like New Yorkers, or self-promoters like many Californians. If you don't ask a Midwesterner directly, they will not tell you about their work, their latest promotion, or about other successes. Having grown up in Indiana, I find that I only feel comfortable talking about myself if it comes up naturally in a conversation. When people find that I speak a foreign language, they will often chide me for not having told them. My response is always, "You did not ask." How can I tell people that I speak Italian without it sounding obnoxious?
Chinese culture also is self-effacing, but in different ways. In Chinese contexts, the proper response to praise and flattery is to deny that the praise is true. I'll never forget my Chinese teachers in Beijing bursting out laughing when, to their comment that my fiancee in the photo I gave them was very beautiful, I said "Thank you" instead of the culturally appropriate denial "哪裡" (literally "where" but meaning "No, you are too kind.") Similarly burned into my memory is Teacher Zhong telling me that his wife could not cook, and that the food we were eating was not very good, just country food, when instead it was a banquet with many delicious dishes. Mrs. Zhong came in, delivered another dish, and agreed with her husband! "Yes, I can't cook; this is just poor country fare." If I ever said that about my wife's cooking, I think she would be very angry.
So it is very odd, to me, that there is a style of bragging in China and Taiwan that seems to violate this modesty. There are not a few men (it is usually men) who will openly brag about how many people they know and how important they are. Recently I met an old acquaintance who had to tell me that, in the years since we last met, he had become an important person. He literally said, "I'm now an important person." Many parents will openly brag about their children's success in school. I met someone recently who informed me that his two children not only both attended National Taiwan University, but majored in the most difficult majors to test into. I used to have an informant involved in politics who would say to me, "I have a lot of friends" (我的朋友很多). In a relational society like Taiwan, having "a lot of friends" is important and very valuable; this was a way of bragging. And yet, to an American ear, it comes across as boorish, even childish. It is like little boys on the playground arguing about whose father makes the most money or has the biggest house. It does not make me say "Wow" but "How pathetic; why is this person overcompensating?"
Americans do brag, but except for outliers like Donald Trump, usually it is done indirectly, like by name dropping ("When I was talking with President Obama last week,..."). Photographs of oneself with famous people are also sometimes used, though many consider that crass. The one place where Americans do brag directly is in Christmas letters, where they let distant relatives and former friends catch up with what they have been doing--listing all the places they went to on vacation, how much fun they've had on their boat on the lake at their summer house, and that Junior was accepted at Harvard. But precisely because the letters are impossible to write without sounding like bragging, they have a mixed reputation, at best. People seem to like to receive them, but also to complain about them.
Modern society, where we deal a lot with strangers and people who do not know us well, does require a certain ability to present ourselves. I've noticed that Chinese students have a very difficult time writing the personal essay for college and graduate school applications. They are often a bit too hard hitting: from a Chinese point of view, Americans are self-promoters, so many students go all out and really sell themselves. They say they are the best in this or that, that their teachers were very impressed by their project, (and of course that they promise to work hard). They come across as a bit over the top to an American ear. This to me underlines how cultural the self-presentation is, and how difficult it is to calibrate it for a foreign audience.
One side of me tends to look at the Chinese practice of bragging as socially awkward and low class, not mainstream Chinese culture. But it is common enough that I am not sure what to make of it. Certainly polished individuals do not do this. I think what I find jarring is that it is the exact opposite of the modesty expected in most contexts, so it makes me wonder why people think it is OK.
With workplace homepages and Facebook and other social media all giving us more chances to present ourselves, finding the right tone is more important than ever, because if you do not put information out there, you don't exist. But if you do it poorly, you're a jerk. But what seems to be a jerk in one culture might be be appropriate in different culture.