I find that my productivity goes up a LOT when I am not interrrupted from work. I share an office right now, and although I really like my office-mate, when she isn't here, the distractions are fewer and I get to work much more deeply.
At one point, I tried to close the door to my office and wrote 'Come In' on a post-it note on the door. I was told that the office is not a closed-door environment and I wasn't to close the door. I talked about working from home and was told that when people say that they are working from home, they are not really working at all.
I have told people that I am busy, and they generally go away. But I don't want to seem like a grouch. Especially to the person sharing my office.
I think that alone time promotes productivity - and so does the larger distance between me and my micromanaging bosses.
I have come to the conclusion that the top man has one principle responsibility: to provide an atmosphere in which creative mavericks can do useful work.
-- David M. Ogilvy