1. Because the landing of stairs is relatively narrow (generally between 1200 ~ 1300) and the security doors are mostly open outwards, it is easy to step on the air if you are not careful in daily use. Especially for families with children, we should pay more attention.
2. From the perspective of geomantic omen, it is easier for the God of Wealth to get out (it is easier to go down than up), but it is not easy for the God of Wealth to keep it, so it is not good to go downhill when you open the door.