I'm glad you're here to defend microsoft when their OS update breaks existing software. Oh wait.. we never see you then.
Apparently your cheerleading is reserved only for Apple.
I spend the majority of my time during weekdays on windows because that is the platform of choice at my employer. There have been stories of patches from Microsoft breaking their "own" software so at my workplace, we tend to be quite conservative when it comes to patches applied in our production environment and we are still using Windows 7 on our desktops and will continue to do so for the foreseeable future. Windows 8.x is a disaster.
But you go ahead and continue with your irrational jumping to conclusions. For the same reason that my company does not upgrade to Windows 8 desktops, It does not make sense to upgrade to Mavericks in a company environment until you have checked for compatibility with all of the software used in your daily workflow. It might make sense to use a test machine to vet Mavericks before committing to an upgrade and as long as you are careful where you surf at work, you should be fine being behind patches or versions for a while.
Remember that no patches can protect you from zero day exploits so common sense is the only defence you have in that case. Don't be an idiot surfing to unknown sites when at work.