its a matter of preference I guess. For us British accent is annoying because its slow. We Americans talk very fast. For the Brits, the American is annoying to hear because its watered down version of theirs
We can talk quicker than Americans if we chose, but it would not change our accent. Speed of communication is more to do with culture than accent. I might be wrong but Brits have a certain degree of pride in how they communicate, for Americans its what they communicate.