Heh, yeah, yet another reason why I don't like Windows: the automatic upgrades that always seem to turn up when they are inconvenient and require a reboot. I mean, when I go home, I don't want to leave my PC running, so I have to stay while it does - what, exactly? So, I only start Windows in a VM and I just pull the (virtual) cable.
Yeah, I HATE that, too! I shuttle my work laptop back and forth from home every day, and it is MOST inconvenient to have that Update notice come up when I am trying to shutdown and go home!
I think MS still thinks that everyone still has a desktop computer, and that it's no problem to just "leave it on" and go home.
So instead, I get to wait while it does a System Restore Point (the majority of the time it takes), then do the install and Reboot (goodbye 30-45 minutes), or "suicide" my laptop by holding the power button, then, the next time I Startup, suffer the bitching and moaning about "Windows was not shut down properly", and then the "Windows needs to Restart" (which pops up when it pleases, and simply HAPPENS if you aren't there to DEFER it, then ANOTHER Reboot (which results in ANOTHER 1/2 hour of virus-scanning), right in the middle of the workday.
OTOH, my OS X laptop does all the downloading of the update in the background, then pops up a Notification to say "Restart to apply the Updates". When *I* deign to Restart, it may spend an additional 30 seconds or so in the grey-screen bootup phase (I assume "applying" the Update) before the Desktop appears (and, unlike Windows, it is "my turn" on OS X after about 10 seconds once the Desktop appears) ... and THAT'S IT.