In previous travels to the US I had slight communication issues with people on the East Coast of US (New York, Chicago) compared to the West Coast of US (LA, SF, Las Vegas, Portland). It seems to me like American people have trouble distinguishing between British, Australian and New Zealand accents, and in particular the people on the East Coast have trouble understanding my accent. Is there any plausible explanation for this?
I also have the experience that many people in the US mistaken me for someone who is from England for some reason. I have no problem picking the American accent, but I am not sure how confident I would be with picking people from the East or West Coast.
I noticed that Australian friends also adopted a slight American accent when living in the US, and I wonder if this also has anything to do with being easier to understand or just adopting the local dialect.
This question should not be taken as a criticism or comment about people in the US, it is just a personal experience that I am seeking some generalization which may or may not be valid.