
That doesn't work, deadboy...
So:
A strange virus causes all characters to live forever. However, this ruins the game and everyone quits! But the characters can't die so the whole of Cantr becomes a zombie-land. Well done, Seko(!)
Also:
England gets good weather. However, every other country gets extremely bad weather: Thunderstorms, gales, hurricanes, you name it. This kills off everyone outside England, which leads to an economic collapse which thrusts the remaining survivors (all English) back to the stone age.
I wish for this wish to have no bad consequences whatsoever.