I don't like it when Windows updates and then decides to restart your machine while you're busy doing something. no way to stop it during the countdown. thankfully that and auto updates can be turned off in control panel, and you can update manually as one would have done during Windows 98.
I never did like my computer doing something without me telling it to, and it includes Microsoft software. especially when it forces a reboot i didn't need at that moment.
I use Windows XP and have all that turned off and a bunch of non-needed services and it has greatly sped it all up plus i don't have any computer troubles other than our crappy wifi router kicking the bucket every 10 minutes.
I lost faith in MS updates after all that Windows Genuine Advantage crap. i saw a brand new Dell Dimension at work having its OEM installed XP being labeled 'pirate' and you couldn't change the background any more. it decided to put this black background with 'Your version of windows may be a victim of software counterfeiting' and resets any background in place of it with that screen each 60 minutes.
Which sucks as i figured MS fixed that issue but apparently false-positives are still out there, along with the update being installed as part of auto updates without notifying anyone. plus the WGAtray.exe app which powers this whole mess is a spyware component, 'phoning home' to Microsoft and i don't condone spyware, even from a legit source.
Source(s):
http://www.pcworld.com/article/12638...s_spyware.html
http://arstechnica.com/old/content/2007/01/8690.ars