Can anybody say "bubble"? It's clear to most people Apple isn't worth the money the stock markets assign it - well over half their cap is investment in the brand. If they ever do anything to damage that or if they do something even remotely wrong, a whole lot of people are going to lose a whole lot of money.
Is it really so clear? Anyone who thinks AAPL is overvalued (including you) can make lots of money by shorting or using puts appropriately. People aren't doing that, so they must not be very confident about Apple's stock price decreasing.
I said it depends on Apple doing something wrong and I can't predict when that'll happen or what it'll be but here are some suggestions: Making the iPhone 7 out of cheese or Tim Cook farting in the wrong direction. Either way, if the markets have shown us anything in the past, it doesn't take much at the moment to send traders into sellmageddon mode.