If you think robots are only designed to tackle everyday tasks that we humans are to lazy to do, then check this out:

Designed by Japan's Ishikawa Oku Lab, this high-speed Janken robot hand has only one task: to win every single game of rock, paper, scissors. So how does it do it? While it's tempting to think that it can actually read the human opponent's mind, it's actually just cheating really fast. Too fast for humans to notice.

IEEE Spectrum has more on how this works:
It only takes a single millisecond for the robot to recognize what shape your hand is in, and just a few more for it to make the shape that beats you, but it all happens so fast that it's more or less impossible to tell that the robot is waiting until you commit yourself before it makes its move, allowing it to win 100% of the time.
So why go to all that trouble? Researchers at Ishikawa Oku Lab say the technology could someday be used to reduce the time delay of human-robot work cooperation.