Windows 8.1 has similar issues.
I support loads of HP Elitepads running 8.1, and they can get into a state where they are fully charged but will not respond at all to the on/off button. I have about five that are useless because of this - I know there's nothing really wrong with them but they will not wake up whatever you do, so they're effectively bricked.
It doesn't help that they mysteriously turn themselves back on when you shut them down, so you can put them away in a cupboard thinking they're powered off when actually they are not, the battery runs down, sleep-of-death kicks in, and after that you can leave them on charge for weeks (I've tried - weeks) and they will never start up again.
It would help (and not just with this problem) if the power button was actually that - a hard switch that kills all power to the system, instead of just some weird kind of soft switch that invokes a software routine which may work if you're lucky and you hold your mouth right, but may just as well go into an endless loop of some kind.
But I suppose that's like wishing for a real live physical connection between your right foot and the throttle control of your car - ain't gonna happen because electronics is "better" and what could possibly go wrong?
The joys!
PS Apple fanboyz, don't even start. Thanks.