MS updates are known to be a potential pain. In my case, with Windows 7, they have worked quite fine. But since the computer and OS are complicated entities, the question remains how certain it can be held, as a total sum. And it's not safe and certain with Linux either - as a matter of fact, like I've noted several times,
if producing an OS would be that easy, we would have OSs like we have mobile phones. Like another point I've made, we
are not in the IT society, we are still
heading towards it. All human error is bound to be obvious, for quite a while.
The difference between important, recommended and optional updates is not, in my opinion scientifically exact. It's a subjective classification. I would recommend to take the important ones, and look at the others before you install them. But, I must say it's hard for me to believe that Microsoft creates harmful updates - with a zillion bits of updates, I'd say it may be difficult for the best expert to create an update "at no risk".
You can disable your updates at Control Panel\System and Security\Windows Update\Change settings. --- But I wouldn't support it. With all its flaws, this OS works.
Best wishes.