There is a Chinese story of an old farmer who had an old horse for tilling his fields. One day the horse escaped into the hills and, when all the farmer's neighbours sympathised with the old man over his bad luck, the farmer replied, 'Bad luck? Good luck? Who knows?'
A week later the horse returned with a herd of wild horses from the hills and this time the neighbours congratulated the farmer on his good luck. His reply was, 'Good luck? Bad luck? Who knows?'
Then, when the farmer's son was attempted to tame one of the wild horses, he fell off its back and broke his leg. Everyone thought this very bad luck. Not the farmer, whose only reaction was, 'Bad luck? Good luck? Who knows?'
Some weeks later the army marched into the village and forced every able-bodied youth they found there by law to serve in the army. When they saw the farmer's son with his broken leg they let him off. Now was that good luck? Bad luck? Who knows?