Sometimes I daven in a Sefardi shul. Recently, a chazan got up and davened - to my great consternation - with the Ashkenazic pronunciation. Why did this bother me so much?? I myself daven with an Ashkenazic pronunciation, like my father, like his father, all the way back to Avraham Avinu [who also wore a shtreimel - as the pasuk says almost explicitly "וישכם אברהם בבוקר" - Avraham got up early in the morning. Now would Avraham get up and not put on his shtreimel???].
The reason it bothered and still bothers me was b/c I felt that is displayed a lack of respect. This is their shul, with their nusach and their pronunciation. You want to say [as chazan] "siaker usishabeir usimageir"? Great. There are a trillion Ashkenazi shuls that wouldn't have it any other way. But this is Sefardi Land. Respect that. Rav Shlomo Zalman would say Brachos with the Sefardic pronunciation under the chuppah of a Sefardi couple. Respect.
This is actually a bigger issue of what people do when there is a conflict between doing what makes them comfortable [in this case davening like he is used to] or doing what makes them uncomfortable in order to accommodate others. This comes up constantly [particularly in a home setting]. A Baal Mussar always looks to see what other people want and need and tries to fulfill those. There are not that many Baalei Musar in the world..... Hence the conflict we often see.
There is also a Medrash that says that when in Rome do as the Romans do. The actual lashon is אזלת לקרתא הלך בנימוסיה - when you go to a town , follow their custom. That is why Moshe didn't eat or drink for 40 days when he went to Shomayim. Up there the custom is to fast - forever. So when visiting Moshe didn't eat. And when the angels came to Avraham they followed the מנהג המקום and ate and drank.
Mussar Haskel - לעולם יהא אדם דעתו מעורבת עם הבריות. Always aspire to bend every which way to make things good for others [within reason of course].
