1. Overall consistency
For a Microsoft product, Windows 7 is quite refined. But it still suffers from needless inconsistency. Why do most of its tools place menus on the left, while Internet Explorer 8 and the help system shove them over to the opposite end? Does the new media-sharing feature (HomeGroup) have zero, one, or two capital letters? Why does Office 2007's Ribbon interface show up only in Paint and WordPad?
2. The names of things
Too often, Microsoft's naming decisions confuse rather than clarify. "User Account Control" has nothing to do with the feature it supposedly describes; "Action Center" sounds like Ron Burgundy's local TV newscast. And an OS that already has a feature called Device Manager shouldn't call a new feature "Devices and Printers."
3. Windows Update
The operating system's built-in patching capability is essential. But Windows Update is also the OS's most irritating carryover feature. Tell it to download and install everything without your further intervention (as Microsoft recommends), and it may still insist on rebooting when you are in the middle of important work — or deny you access to your computer altogether while it installs updates.
Windows 7's Federated Search lets you add external sources like Flickr and YouTube to Windows Explorer searches. But the OS doesn't help you find those sources and doesn't mention Federated Search in its help system.
Help ... needs help. Some sections target nerdy command-line aficionados; others address clueless newbies. Few sections focus on intelligent-but-busy users of intermediate experience.
Press Windows-Tab, and you get Vista's fancy 3D task switcher, which pointlessly requires you to cycle through tasks one by one. This duplicates the functionality of Alt-Tab instead of enabling you to get to any task in a couple of clicks, as Apple's similar Exposé does.
Win 7's Backup and Restore Center no longer requires you to devote an external hard drive to a full system backup. But it still isn't as easy to use as Apple's Time Machine. And Microsoft's decision to put network backup only in Windows 7's priciest editions is just silly.
Having multiple versions of Windows is fine in theory. But in reality, their minor, subtle, and arbitrary differences invite confusion. Misleading names like Windows 7 Home Premium — the only Windows 7 Home version available in the United States — don't help.
9. Internet Explorer 8
Windows 7's bundled browser is perfectly adequate. But it's playing catch-up with innovative competitors such as Firefox and Google's Chrome, not setting new standards.
10. Document viewing
Like Vista, Windows 7 lets you create application-independent documents that use Microsoft's PDF-like XPS format to retain their original formatting. But PDF is pervasive and XPS hasn't caught on, so wouldn't it be infinitely more convenient if Windows 7 supported PDF out of the box?