Flight MH370 Disappearance

I really cannot wrap my mind around how a plane could disappeared. If my crappy iPhone could pin point my location with such accuracy, how can we lose a plane in this modern interconnected technological world? What about the famous aircraft black box? And aren't all plane designed to float in water, that's why the passengers are trained to wear the lifejacket and to show you the exit so you could slide your way down to safety. This would gives you the impression that if something happened to a plane, the sea is the preferred way to land vs a jungle.

Many said that the pilot have enough time to broadcast an emergency message but none came. So it suggest a sudden incident - an explosion perhaps? Or someone murdered the pilots and crash the plane.. if it is the former, is it because of our Malaysian substandard again?

From CNBC:
Arnold Barnett, a longtime Massachusetts Institute of Technology specialist in aviation safety statistics, said that prior to the disappearance of Saturday's flight, Malaysia Airlines had suffered two fatal crashes, in 1977 and 1995. Based on his estimate that Malaysia Airlines operates roughly 120,000 flights a year, he calculated that the airline's safety record was consistent with other fairly prosperous, middle-income countries but had not yet reached the better safety record of airlines based in the world's richest countries.