I recently acquired an iOS device making my exposure in the last year to Android, Blackberry and iOS. There used to be an old joke screenshot going around saying "Windows has detected your mouse moved. You must reboot for this change to take effect." The contemporary equivalent seems to be "Apple has detected you want to do anything - you must re-enter your password and possibly your username to proceed."
I kept count of how many times I had to enter my credentials from getting the device, doing an iOS 5 upgrade and putting some Google apps on the device. In the end I had to enter my apple id 7 times across iTunes and the device, and my Google one 12 times. Why the heck does iTunes want to re-enter my id in multiple different places? Why on earth do I have to enter my apple id multiple times in different Apple provided programs on the device? The Google issue seems to be because they have hybrid native apps with web based components with no sharing so you keep entering the details all over the place.
I want to enter my credentials zero times. Amazon figured that out with their Kindles shipping the devices pre-authenticated. Android makes you enter your id only once and then provides platform infrastructure for it to be shared across participating apps, although not all third party ones do.
As someone following best practise (long passwords with a variety of content), having to enter them is extremely painful on devices due to keyboard modes for numbers, punctuation and capitalization, and masking of what you have already typed etc.
One Apple fan boy I talked to seemed to think this was perfectly reasonable behaviour! I can only conclude the Apple faithful have short passwords they are happy to type over and over and over again.
One "attention to detail" thing highly amused me. The icon for the weather app shows a numeric temperature. If you change your settings between C and F then the icon changes, but not immediately leaving a nonsensical number visible for quite a while. But most absurdly, why not just make the number be the current temperature rather than something that seems credible but is wrong? Or leave it out completely.
There are also massive inconsistencies between what settings live within an app versus selecting the same app from the Settings app. It almost seems random which place you have to look in.