If ghosts can walk through walls and glide down stairs, why don't they fall through the floor?

No mass means gravity doesn't pull them down.

They do. That's why we never see them.

you're not supposed to ask questions like this....😳

Who said they don't?

They don't wanna

They prefer to levitate? 🤔

Because fiction decides which rules apply for dramatic effect rather than reality. Also, they float and don't actually walk. So they COULD disappear into the ground if they wanted.

Because ghosts don't exists.