I've always believed strongly that Apple's success as a hardware manufacturer was impossible without its success at making software that "just worked". Their minimalistic style appealed to those that were fed-up with feature blot and wanted just a few things as long as they worked perfectly.

Apple has now gone in strange direction - it still offers very few features but they barely work and are mostly extremely confusing. Read the excellent article by Kontra at counternotions.

Here are some of my pet peeves which mostly overlap with what Kontra has on his article.

1. ITunes Match. Not sure why it is all of nothing. Not sure why I cannot copy some music on my phone and make the rest available to me for download when I need to. 
2. iCloud. Why do still need dropbox or google docs to share documents?
3. Photostreams. Who really came up with the functional specifications for this one? "Shared photostreams" that only one person can add to?
4. iTunes. The less said the better but even after being on the market for 11 years, why can I still not sync a complex rule-based playlist?
5. Podcast app. Easily the worst app that apple has ever delivered. I still don't understand how this made it to the app store.
6. Apple ID. How many places on the phone do I have to specify my ID? App store, iTunes, Find My Frinds, iCloud, iMessage and so on. Make it easy. If I want a different one for each - I will ask for it
7. Apple TV. Why does this keep losing connection to the internet and why does it need to be rebooted so many times?
8. Photo syncing to iDevices. How come I suddenly lost all ordering? This is a biggie for me and has almost killed the photo viewing experience for me. I get 10 year old photos and have to scroll hundreds of times before getting to newer photos. 
9. iTunesU. Why no option to play a course in ascending order? Who ever takes a class from the lass lecture to the first? Apparently this feature exists in Podcast where it probably matters less but doesn't in iTunesU where it is a must!
10. Newsstand. Love the concept but I've never had an app successfully update its content regularly. Huge pain to be on the train underground and realize that The New Yorker or the New York Times edition that Newsstand told was available - really isn't. 

I can go on but these are my top 10. Most have nothing to do with UI but only to do with how these things work - or really - don't work.