Work forces me to use Outlook (the web version) and it's the worst mail program I've ever used. I repeatedly need to mark the same mails as read (last week I got a mail which kept marking itself as unread each time I switched to a different folder and back). A more minor, but still ridiculous, thing is that I can't create a top-level folder named "Calendar" (WTH?). But you'll be glad to know they localised this bug, so you actually can't create such a folder using the word for "calendar" in whatever UI language you chose. The default theme makes it really hard to distinguish mails which are read and which are not. I could go on and on.

I have no idea how a company like Microsoft releases such a turd to the world. And supposedly they're focused on "The Cloud"(tm) now, not Windows. So it should be in a better state than Windows.

When it comes to Windows, I love the overall kernel design. But when it comes to using the system, it seems to really lack polish. The myriad of little dysfunctional details (mostly in things which were added after Windows 7) just kills my ability to work with the system without getting angry at it.