From a 1999 Douglas Adams essay (via BBC's Tom Chatfield):

We no longer think of chairs as technology, we just think of them as chairs. But there was a time when we hadn’t worked out how many legs chairs should have, how tall they should be, and they would often ‘crash’ when we tried to use them. Before long, computers will be as trivial and plentiful as chairs (and a couple of decades or so after that, as sheets of paper or grains of sand) and we will cease to be aware of the things. In fact I’m sure we will look back on this last decade and wonder how we could ever have mistaken what we were doing with them for ‘productivity.’