In the US, the really noticable accents have slowly been disappearing since the 1950s. With the mobility of large segments of the population, the use of non-descript dialects in television and movies, we're slowly bleaching out regional dialects. Don't get me wrong, there are still some very noticable dialects in use, but they are probably less dramatic now than 50 years ago.
When I first moved to the south, I expect to be surrounded by the southern dialect, but was surprised how small a percentage of the population actually speak this way. Yes, there are still a few with very strong accents, but there are so many transplants down here that a lot of what I expected didn't exist.
My fascination with accents began when we had an Australian exchange student in high school. I was fascinated listening to him speak. Then I went to the UK for six-months in the 70s and was in heaven. I loved to listen to the variety of accents and was surprised that they were just as fascinated my my accent - which I didn't think I had. I was even more amazed at how tge accebts differed in varous areas of London, the more rural areas, and then even more so in Wales and Scotland. At times I wondered if we had a common tongue.
An interesting incident happened about a week before I left, when a student from France moved into the same place I was staying. I tried to speak to him, but we were having trouble communicating. He eventually told me that he only spoke English, not American, and that's when I realized I tended to use a lot of slang terms, metaphors and other terms that were different than those used across the pond. After that, I tried to choose my words more carefully.