There was an old farmer in the country. One day, his stallion broke its fence and ran away. His neighbors said "that's so bad!" The old farmer just shrugged and said "Who knows?"

The next day, wanting some oats, the stallion returned. And, it brought three wild fillies with it. His neighbors said "that's great luck!" The old farmer just shrugged and said "Who knows?"

The farmer's teenage son went out to break one of the new horses. It bucked him, and he broke his leg. His neighbors said "what horrible luck!" The old farmer just shrugged and said "Who knows?"

The army then came around, conscripting young men to fight in a war. Because of the broken leg, they didn't take the farmer's teenage son. The neighbors said "what great luck!" The old farmer just shrugged and said "Who knows?"