3. Waiters/waitresses

Intelligent service robot serves clients in snacks bar in Chengdu city, capital of Southwest China's Sichuan province, Dec 14, 2014. [Photo /Chinanews.com]

In a robot restaurant in Harbin, 20 robots are in charge of all the restaurant's various services. There are delivery robots, noodle-making robots and even entertaining robots.

When a customer enters the restaurant, the usher robot will stretch out its machine arms and say welcome.

In the United States, a bar-tending robot is designed to make cocktails according to their customers' mood.

Of course, before the intelligence of robots is developed so they can communicate, customer experience of robot-waiting might not be as good as human waiters/waitresses.