What does it mean for the neighbors downstairs to walk up the stairs with their heads up at the door?

This behavior may be that the neighbors downstairs are doing something supernatural and superstitious, such as exorcising evil spirits and making money. It is also possible that they want better luck and put worn-out shoes at the door to show their bad luck in the past. In a word, you need to observe and understand more about the specific meaning of this behavior before you can draw a conclusion.