Why does feng shui think it is best not to set up entrances and exits of buildings?

As a form of urban three-dimensional traffic, underground passage plays an important role in urban traffic. In order to make full use of resources, many underground tunnels have opened shops. Although it is also at the mouth of the underground passage, because its direction is up and down, this sinking pattern is a taboo in geomantic omen, neither gathering gas nor wealth, but also leading 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 for the exit to be next to the entrance of the underground passage, because although people enter through the door, they will soon get lost through another exit. If the mall does not receive popularity, the fortune will naturally not be too good. There is one exception, however, which is the underground passage leading to the subway station. Different from the ordinary underground passage, people who pass through the passage will gather in the subway station, and the entrance and exit of the subway station will also bring a large number of people, and the popularity will naturally flourish.