The navigation gestures and movements on iOS are a prime example.

They're plenty intuitive, but they're obviously timed for the slowest possible user using them for the first time - so by the hundredth time you try to do something, you're getting really frustrated by having to make grand, exaggerated gestures to get the OS to understand what you want, and I frequently find myself having to repeat actions 2-3 times for them to "take".