When it comes to updates I am careful. Once I have left Windows Update to update my computer and my network printer stopped working. I discussed the problem it with uncle Google and he found out that it's because of the withdrawn support for Raw Sockets in Windows XP SP2. But the funny thing is that this update is not present in only one particular patch. Indeed it's present in about 60 patches including the patch for Spider Solitaire. Does Spider Solitaire has anything to do with networking? No. It's an offline game. And even if you go to update detailed description there still isn't any note about any change in networking.
In another case I couldn't connect to WebDAV on Vista. Windows Vista was a new operating system and I expected some problems. Hence I updated the system to a newly released service pack. It took a whole day to download 6GB service pack and all the updates. But WebDAV still didn't work. Fine. I asked uncle Google and he found a patch from Microsoft, which is not automatically deployed with Microsoft updates. And it somehow helped (I have got from the second step of a wizard into the third step. But after two days of debugging I gave up in the fifth step from seven steps and installed Total Commander with WebDAV plugin and I got connected in less then five minutes).
If the updates I want aren't automatically deployed with Windows update and updates that I don't want are sneaked as Spider Solitaire update, how can I trust Windows update?