Hey, you don't own any Netflix stock, do you? Because if you do, bad news: the stock nosedived 13% in after-hours trading last night.Netflix's rough evening was triggered by its slower-than-expected growth: the streaming giant missed its subscription numbers target by more than a million subscribers. Netflix added just half of the 1.2 million new American subscribers it had projected, and it came up half a million short of its 5 million projected newcomers internationally.Netflix, of course, would like everyone to remain calm. They're citing internal mistakes with their forecasting. In other words, Netflix is growing normally, but the projections were way off – or, at least, that's the company line.Elsewhere, observers are laying a bit more blame at the feet of Netflix's brass. Netflix's massive investments in original programming have yielded more quantity than quality, which could be one reason that the shine is off the streaming world's once-untouchable leader.Netflix's stock has crawled back a bit in morning trading, but as of this writing it's still more than 9% lower than it was at yesterday's close.