I think you have watched the terminator series in which Arnold plays the role of a machine which was designed to save humanity. Moreover, many other aspects were shown in that movie regarding robots.
These days defence is the key area in which almost all the governments invest a lot of money for its betterment. So the question arises that how the manpower in army would get boost with the technology of robots. These days the technology of artificial body parts is being looked upon. Therefore, hydraulic systems combined with robotics would be used in making equipment for legs and arms and other body parts which would boost up the strength of warriors in warfare by many times. Additionally, it would also help to increase the amount of time to carry the operations as the support system in such body armors would help to carry out activities like running, climbing and what not and hence the warriors would feel less tired.
In 20th century, due to revolution of machines many people suffered unemployment as the machines were way more productive than the labor. One machine could do work of tens or hundreds of people. Similar thing is going to happen now as the age of robotics and AI has begun. In restaurants, the jobs of cashiers would no longer be there as the customer interfaces would be there in place. You must have seen the videos of the inside view of some automobile industries in which the work assembling,washing and many other things is done by robotic hands. Maybe the food would also be cooked by robotic hands in the coming times. Machines would learn the behaviour of humans and serve many purposes. They would be used to do the works of builds at various construction sites. Maybe machines would be doctors one day and that day is not so far.