Granted. The world is cured of Motor Neuron Disease. However, Stephen Hawking then uses his new found verbal linguistic talents to convince the entire world's population to constantly wear tweed jackets. Subsequently, the fashion industry is destroyed. Models and designers then run riot across the world forcing innocent people to wear clothes and then photographing them. The government then passes an extreme law executing everyone who has ever been photographed ever. 99.99% of the world's population are killed leaving only the executioners. They realise they are the only people left on the planet and decide to cheer themselves up by forming a backgammon league. The rest of the world's population dies of boredom. Happy with your wish now are you? Eh?!!

I wish I was in prison