I have read a story named "A clever donkey" before. It really taught me something meaningful. Here it goes.
There lived a salt seller in a small village. He had a very hard—working donkey, on which he used to carry a salt bag to the market every day. On the way there, they had to go across a river which was not very deep.
The other day, the donkey suddenly fell over when crossing the river and the salt bag also fell into the water. Because the salt dissolved(溶解) a little in the water, the bag became very light to carry. After noticing the change, the donkey felt surprised but happy. It was much easier to carry the bag than before. From then on, the donkey became "clever" and started to play the same trick every day.
A few days later, the salt seller came to understand the trick and decided to teach the donkey a lesson as a punishment. The next morning, he put a cotton bag on the donkey. When crossing the river, again it played the same trick, hoping that the cotton bag would still become lighter. But the dampened (浸湿的)cotton became rather heavy to carry and the donkey suffered a lot. It truly learned a lesson and didn't play the trick anymore after that day. Of course, the salt seller was pleased with it again.
In our daily lives, there are some people acting as the donkey did. Once they taste something sweet, they will dream of candies all the time. However, we have to know one thing-Good luck won't always favor you.