People will not be happy because of the same joke, but will continue to be sad for the same reason.

The professor told a joke in class and everyone laughed.

Half an hour later, the professor told the joke again, and only half of them smiled slightly.

When the professor told the joke for the third time, no one laughed any more. Finally, the professor said, "Yes, since you are unhappy again and again because of a joke, why are you always sad for the same reason?"

Yes, many times when I am listening to something that surprises us, you may be really interested in it for the first time and pay close attention to it, but when you listen to it repeatedly, you may gradually lose interest in it and sometimes get bored.

But why sometimes a bad thing can repeatedly affect our mood and make us feel sad?

This is something worth thinking about by all of us. There are many disappointments in life, but we can't keep falling into them. We can't let them affect our mood and make us feel sad continuously. We should forget bad things as soon as possible, just like we listen to jokes.