What does Monday morning quarterback mean?

What does the fortune teller mean when he says that I have twelve post horses in my life?

The post station is a post horse and a means of transportation. In ancient times, it was said that the post horse was equal to the modern postman. In ancient times, there were many post horses, that is to say, he was either a cavalry or a messenger, and he had to ride more horses to change. Besides herders, modern people also ride horses. Most people use cars instead of horses, so there are more post horses and cars, which means more communication, more mobile phones and more computers, which can also be compared with comparable occupations. Fortune-telling is just an analogy, without specifying anything specific, so I don't know what it is.