The very origins of DOS and Windows tells you something about the way it works now. I remember reading that in the original piece of software that Microsoft was hired to write, BASIC for the original IBM PC, one of the most difficult tasks was to get the interpreter to fit into the memory they had available in the machine's ROM. We're talking very primitive hardware here, and quite the engineering feat to work within those constraints.
One of their decisions speaks volumes about the philosophy that suffuses much of Microsoft software today. Because memory was so tight, they couldn't afford the number of bytes to print the traditional "READY>" on the screen, so they chose "Ok>" instead. If any of you remember using the BASIC built-in to the original PC, you'll remember that "Ok>" prompt.
Why say anything at all? If resources were tight, why not just provide a simple prompt when everything is OK? Like ">"? This is exactly what the Unix guys did when they needed to be frugal with resources -- they invented the idea that "no news is good news".
Take this simple distinction, "Ok" vs. "Silence", and multiply it by millions of lines of code and decades of development. What you end up with is the most annoyingly chatty software you can imagine, Windows and Office. They constantly pester me about things I don't care about ("You have un-used icons on your desktop", "You're network cable is unplugged", "Let me go harvest clip-art from the Internet for you", etc.). An alternative is Mac OS X, which is sublimely quiet most of the time, and of course command-line Unix which is positively mute (until it needs to tell you something that you really need to know).
Obviously, chatty software annoys me (I've blogged about shortcuts to turn off some of the annoying balloons in Windows before). But I had never thought about why it is that way until I remembered that, when given the choice between silence and verbosity, Bill and Paul chose the latter.