a couple of donkeys crossing a body of water

There was a salt seller who used a donkey to transport bags of salt to the market every day. One day, the seller and the donkey had to cross a small river to reach the market. However, the donkey suddenly stumbled and fell into the water, causing the salt to dissolve and make the bags light. Which made the donkey very happy. From that day on, he started repeating the same trick every day. The seller discovered this trick and decided to teach the donkey a lesson. The next day, the seller filled the bags with cotton and placed them on the donkey's back. When the donkey tried to do the trick again, he fell into the water as he did before. However, unlike previous times. His weight increased significantly, which made the donkey have great difficulty getting out of the water. At this moment the donkey learned his lesson and realized that tricks will not always be successful. And luck will not always be in his favor