Why does Feng Shui believe that it is best not to set up entrances and exits to buildings?

As a form of three-dimensional urban traffic, underground passages play an important role in guiding urban traffic. In order to make full use of resources, shops have been set up at many underground passages. Although it is also located at the entrance of an underground passage, because its direction is from top to bottom, such a sinking pattern is taboo in Feng Shui. It neither gathers energy nor wealth, and will also lead people to other places. Even if the entrance of the building is not next to the entrance of the underground passage, it is not good if the exit is next to the entrance of the underground passage, because although the flow of people enters through the door, they will quickly lose through another exit. If the commercial building is not popular, your fortune will naturally not be very good. But there is one exception, and that is the underground passage leading to the subway station. Different from the flow of people in ordinary underground passages, the flow of people passing through the entrance will gather in the subway station, and the entry and exit of the subway station will also bring a large number of people, and the popularity will naturally increase.