The old man lost his horse: a 200 BCE Taoist parable on luck and fate (wikipedia.org)
The old man lost his horse (but it all turned out for the best) (Chinese: 塞翁失馬,焉知非福; lit. 'The old man of the frontier lost his horse', 'how could he know if this is not fortuitous?'), also known as Bad luck? Good luck? Who knows?