Robots may be difficult to define. Even experts do not all agree on what robots should all have in common. The grey area of disagreement includes the mechanical tools designed execute work and automated toys. Are these machines 'robots'? A purist would define a robot as a programmable appliance having sensors of some type and decision-making abilities, based on sensor input. Others would include mechanisms which simply can operate on their own. The term has come to include virtual as well as physical devices.
The concept of robotics predates the word robot, itself, which was coined from a German word meaning work, and first used in the play 'RUR', by Capek in 1920. The idea of artificial people or animals dates back to ancient times, and some were built as early as 4 BC. Leonardo da Vinci designed a humanoid robot in the late 15th century, although it is not known if it was ever built.
Robots can be categorized by their purposes, as for example work, entertainment, exploration and weaponry. The dangers posed by physical robots are both real and imagined. People have been killed by robots in the workplace, and certainly any machine is capable of inflicting harm. Speculation about the possibility of robots utilizing their artificial intelligence to attack and overcome their creators has provided the plot for a plethora of literature and film. Automated weaponry, of course poses a real and possible danger of catastrophic events.
Today the popular interest in robotics is much less menacing. It includes games which test the programming ingenuity of players to design virtual robots to challenge their opponents. Hobbyists are becoming adept at designing and/or building their own robots. If your science background is not strong, you can buy a kit with the materials and instructions you will need.
All of these pastimes are worthy of the time spent on them. They impart knowledge and develop skills that are transferable to other aspects of life. Even President Obama felt the popularity of robotics was newsworthy and encouraged young people to continue their pursuit of science and engineering and to make things, rather than just consume things.
Don't let all this talk about what is good for you discourage you, however. The reason so many people are doing this is for fun! We love robots.