The answer to the riddle, "I have three eyes and one leg, obey me or you will be sorry" is "Traffic Light".
A traffic light has three eyes such as the red, amber and green lights, the leg is the pole holding it up. Drivers/motorists beg the light to stay green as they're approaching. Obey it or you'll be in trouble.
Thank Nottingham Engineer, John Peake Knight for making drivers stop and go at busy road junctions. He was a railway manager who specialised in designing signalling systems for Britain's growing railway network and the one responsible for the world's first traffic lights that were installed near London's House of Commons in 1868.
In recent news, the Italian food industry has said it is deeply concerned by the UK government’s decision to recommend traffic light colour coding as part of its front-of-pack nutrition labelling programme, saying that it is not based on sound science. Check out full details here.