What does it mean to say, "I have tasted everything, only Yangmei is a little sour" ... "

I have tasted all kinds of flavors in the world, and only the sour taste of bayberry is my favorite. "Everything in the world has been tasted, only Yangmei is a little sour" is a poem written by Taitai students of Huizong in the Northern Song Dynasty. According to the story introduction of Huizong Poetry Collection, it can be seen that "everyone in the world has tasted it, but Yangmei is a little sour", which means that all the flavors in the world have been tasted, and only Yangmei's acidity is my favorite.