Why do fortune tellers know what happened in my family before?

Fortune-telling can be divided into four pillars and eight characters, six hexagrams and fortune-telling (physiognomy). We can know the past because there is a lot of information in eight characters, divination images, palms or faces. If it can be inferred through careful study, the past is accurate, but the future may not be accurate. This is because the past is a fact that has happened and has been branded on people. But this is fate, which cannot be changed. People are still lucky and can be changed. Going out for a walk in the east and west, the people and things you meet, the feng shui at home or at work, and even the changes in the feng shui of the ancestral graves may all affect a person's luck. Sometimes, it will change some people's numerology. For example, a person, a fortune teller said that he would have an accident, but he didn't believe it, so he drove. As a result, he only met a driver who ran a red light that day, and it was nothing to brake suddenly. It doesn't seem accurate. In fact, this person subconsciously has a dike, unconsciously slowed down the speed and raised his vigilance. I don't know if you understand.