Learn to be rude-I have found that people soon get the message and cease talking to you if you don't answer:

That's not necessarily guaranteed, in my experience. Some of the worst chatterboxes also have extremely thick skins, or else labour under the impression that you're listening to them even though you're not responding.

I have similar problems with interruptions, plus the fact that my day-job of writing software exercises similar mental muscles to writing fiction, so I'm often out of mental energy by the time I have the opportunity. So I frequently write late at night, when I can get time to hear my own thoughts.

I don't go with the idea that just banging out a thousand words at a time is good.

 
I agree. However, I do think most writers suffer from sitting too long in the middle of two extremes: keep up a high word count no matter what and don't write anything at all unless you know it's going to be totally inspired. I used to think these two approaches manifested in two different kinds of writer - the commercial and the artistic, for want of better terms. But now I think it's a dichotomy that exists inside most individual writers. A lot of psychic energy is spent trying to balance these two extremes in oneself. But maybe it's better to just embrace their reality and use the creative tension between the two to one's own end. For example, if you're not feeling creative, push on anyway and keep the words flowing until the crackle and fizz of their passage attracts something new. Or if you're writing at a hundred miles an hour, deliberately pause and resist the momentum of accumulation in case it's missing something important in the surrounding view.