Lots of people -- I'm one of them -- find that switching whole windows seems to pop the mental stack.
That's really interesting! I have the opposite problem - switching windows doesn't pop my mental stack, but if there's anything on the screen other than what I'm trying to focus on, it keeps diverting my attention and ruining my concentration. Fullscreen emacs on OSX (without even the system menu bar!) is just awesome for me.
Here's a screenshot of what my entire desktop looks like when I'm working on code: http://abstractnonsense.com/desktop-2013-02-17.png