It's not quite as well-publicized as Antennagate or all those "overheating" iPads, but there's an annoying little issue still prevalent in iOS 5 that you might have experienced. It's hard to pin down the cause--although Apple's discussion boards are filled with complaints from photo junkies--but if you've ever gotten stuck on the "Waiting for items to copy" step of an iTunes sync, you're not alone.
For most of us (this writer included) it's an occasional nuisance. It generally pops up at the end of a lengthy sync but there doesn't seem to be a consistent culprit. Apple's discussion boards are filled with complaints about the so-called iTunes sync bug, with situations ranging from genius results to large photo libraries. It seems to be a bit more prevalent on Windows, but there are certainly a healthy share of Mac users at their wits' end, too.