Why did Wang Xizhi cheer and clap his hands in unison after reading the Spring Festival couplets?

Wang Xizhi, a calligrapher in the Eastern Jin Dynasty, moved from his hometown to Shaoxing, Zhejiang. At this time, it was the end of the year, and Wang Xizhi wrote a pair of Spring Festival couplets for his family to stick on both sides of the gate. The couplet is: "Spring breeze, spring rain, spring scenery, New Year, New Year's new scene." Unexpectedly, because Wang Xizhi's calligraphy was the best in the world, he was highly respected by people at that time. As soon as this couplet was posted, it was uncovered at night. After the family told Wang Xizhi, Wang Xizhi didn't get angry, so he started writing and asked his family to post it again. This is written like this: "Ti Ying Beixing, the southern suburb of Yanyu, the composition of Wang Xizhi's strange book Spring Festival couplets in the sixth grade of primary school." Who knows, at dawn, it was uncovered again. But this day is New Year's Eve, and the next day is New Year's Day. Seeing that Spring Festival couplets are hung in front of every household in the neighborhood, but there is no one in front of my house, Mrs. Wang is anxious to urge her husband to find a way. Wang Xizhi thought for a moment, smiled and wrote another note. After writing, he asked his family to cut out a couplet and put the first half on the door: "It never rains but it pours." Sure enough, someone stole it at night. But when I look at it in the moonlight, I can see that this couplet is too unlucky. Although Wang Xizhi is a famous calligrapher, he can't take down this couplet full of dangerous predictions and hang it up. The thief had to sigh and slip away in the dark. At the dawn of the first day, Wang Xizhi personally went out yesterday to post a half-cut. At this time, many people are watching. When you look at it, the couplet becomes: "Happiness never comes to this day, but it never rains but it pours last night." "When people saw it, they cheered in unison and clapped their hands.