I hate how fickle and twiddly video card drivers are. It seems that every time I upgrade it fixes one problem and introduces another. I guess you therefore shouldn't ever upgrade when nothing's wrong, because when I upgraded my ATI drivers I lost the ability to play DVDs and Windows Media files properly, though oddly enough MPEG and DVR files were fine. So, back to the old ones.
It really bothers me how often random problems with computers can be fixed by new video and sound card drivers.