As far as fuck-ups go, yesterday’s iOS 8.0.1 update was a biggie, with users of iPhones 6 reporting lost cellular service and Touch ID functionality. QA is complicated, but it’s embarrassing to see such basic and core services broken by a relatively small update. How was this not caught earlier?
Even the workaround has its issues. Apple, in the linked support document, recommends downgrading to iOS 8.0 until 8.0.2 is ready in a few days. But downgrading will also make Health stop working, presumably because of the HealthKit fixes in iOS 8.0.1 causing compatibility issues. Bizarre.