Bluetooth
Of all the fancy-dan things on my phone, bluetooth is probably the least reliable!
Anyone remember those radio-controlled cars you might have had as a kid? I went to a Radio Controlled Car themed birthday party aged about 12 in someone's back garden. About 20 of us trying to race our cars, all working off similar radio frequencies... absolute chaos, cars everywhere.... my car won because it was so old that it had an actual wire connecting the car to the controller, thus didn't use radio!








