Broken DAAP music server playing - can no longer play music with iTunes from my streaming server (since like iTunes 10).
The rest of iTunes - plenty more comments detail this.
Usability: removal of the scroll arrows from the UI. If you're not on a multitouch pad, or a wheely mouse, hey, just get used to it. F.U. Apple.
Intentional removal of their OWN Fax Modem (yes, a software issue, as the Fax Modem dongle did its processing on the Mac CPU). Only found out about this item I only kept around to receive rare faxes when I suddenly needed to receive a fax. Doesn't work, and doesn't say why: upgrading the OS was enough to break it forever. Would've been nice to hear that BEFORE I upgraded.
Apple Mail: steaming pile of turd. I've had Apple Mail mistakenly associate emails with an account identity, then when I delete that identity, all the mail goes away with it. Have had Apple Mail silently mangle emails for months before I found out. Wish there were some other option other than this featureless pile of feces, but there's really not anything that's both better and less buggy. Eudora was, but it's been out of maintenance for maybe a decade.
Breakage of their legacy software: In the last month I've been moving a huge pile of offline CD and DVD stuff back to magnetic storage (since it's cheap now), and am amazed that so many presentation/multimedia/game/video titles will never run again, because Apple has dropped their Classic and Rosetta emulators. Stuff of a similar vintage could probably be at least opened on Windows (if not actually run well).
AppleLink>eWorld>iTools>.mac>mobile me>iCloud: Apple has shown a complete inability to focus on maintaining online services. They announce an infrastructure, allow users to build something significant on it, then shut it off without a thought. #epicfail. I wouldn't trust Apple with any of my data online.
There's plenty more wrong. The list goes on...