Smartphones have changed the world, this much we know.
But as with all things tech, they're prone to blue screen of death moments from time to time (my phone has a little image that looks like this in the top right hand corner of the screen, and it took me months to figure out how it got there).
3G, 4G and the WiFi bars are ones you're probably a little more familiar with. But what the heck is the 'E' for when you sort of have signal but everything loads really slowly?
Well, apparently, the 'E' actually stands for EDGE, or 'Enhanced Data Rates for GSM Evolution', which is not that catchy, but pretty important, laying as it did the groundwork for the faster mobile internet G. You'll still see it anywhere that doesn't have a 3G or 4G network (ie most of Britain, despite what your provider says).
There's also the griefpit known as GPRS, or General Packet Radio Service, which means you're definitely off the grid. Unless scrolling around on your phone's mapping app is your thing.