From Electronic Life:
The history of the telephone provides an instructive example of what happens as a technology becomes widespread. Anyone over the age of fifty can probably remember when telephones had no dials. To make a call, you picked up the receiver and waited until an operator came on the line. You told the operator the number you wanted, and the call was placed for you. If you placed a long-distance call to some other city - a very exotic undertaking - you'd hear the operators talking to each other in their regional accents, arranging to route your call through their individual switchboards.

By the 1940's, this charming system was breaking down. There simply weren't enough operators to work the switchboards. In fact, projections of future telephone growth suggested that there weren't enough women in America - even if they all became telephone operators - to make the system run.

The solution was direct-dial telephones, which demanded all sorts of automatic switching devices and complex thingamajigs. This flashy new technology obscured a basic truth. The telephone company had actually solved the problem of insufficient operators by making everyone into his own operator. The number of telephone operators now equaled the telephone-using population.

For nearly everyone, the telephone provided the first experience of direct interaction with a computing machine. People had to learn the harsh rules of computer interaction: numbers only, and number presented in specific order. The telephone responded to exactly what you dialed, whether you'd made an error or not. There was no friendly human voice to catch your mistakes.

After an initial period of grumbling, people discovered they preferred direct dialing. It was faster and it was totally private. The few situations where an operator was still required, such as overseas calls, became irritating. The fact that you couldn't do it yourself was now perceived as a flaw, not a virtue.