Last year's big issue was a battery-life problem, which appeared to rapidly drain the iPhone 4S' power source for no apparent reason. Customers took to Apple's iPhone forums to complain about the issue, and some reported up to a 20% drop in battery life in an hour -- even when the iPhone isn't being used.
Apple acknowledged the problem as a software bug and sent out an update meant to fix the glitch. But many users continued to complain that their battery life suffered, even after the update.
Apple CEO Tim Cook issues apology for the widely panned Maps app, saying Apple "fell short."