There is a subtle context of ‘foreplay’ I feel when it comes right down to it. The typical British English user is more than likely to seek words that best articulate a fully formed thought or even a passing idea not yet fully crystallized.
The speech therefore comes out much more finessed than a typical American English user is able to deliver.
I am not saying either one is wrong – just that they (the Brits) utilize a somewhat different set of objectives in their choice of words. The one (Brit user) is predisposed to consider all the niceties that the language can bring to bear on the conversation, where the other (Yank user) would tend to parse it down to the bare-bones, unconcerned with niceties or embellishments – so long as the point gets across.
I do not believe there is any overt or covert belief that American’s come across as abrupt…just that their use of the ‘Queen’s English’ is somewhat…’improvised.’
What I find really neat about the American prose/conversation style is that the focus is on getting the key points across always. It is not too concerned with proper spelling, or grammar or enunciation, etc. If the text or the spoken word is clearly understood and can be acted upon, that is satisfaction enough. This makes for communication that is economical, crisp and readily understood. Many of us who come from backgrounds where the Britain ruled, and espoused the Queen’s English, may tend to be critical of this lack of attention to grammatical finesse and detail on the part of the our American brethren, so to speak. But this easy style kinda’ grows on you…and you soon begin to love it’s unpretentiousness and realness!