Imagine reading a science fiction novel when you were a kid that said this:
The Global Positioning System (GPS) is a space-based satellite navigation system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites. It is maintained by the United States government and is freely accessible to anyone with a GPS receiver.
Imagine the book goes on to explain that everyone has a GPS receiver on them at all times, built into their handheld computing device.
Of course, the quoted paragraph is actually from the Wikipedia entry for GPS (and the bit about everyone carrying one is just true). We take this technology for granted now, but it’s pretty mind-blowing. I mean, remember getting lost? That sucked.