Why shouldn't we sit infront of the door? (science vs superstition )

We are always advised not to sit in front of and door. Specially this line is said by our grandmothers. Is there any scientific reason behind this?

Let us understand the fact that why they used to say that? 

Definitely they once observed many incidents for which they used to say so which became a saying. If you sit in front of any door then usually you will block the getaway. That means if you sit there then people who will try to to enter through the door, they will face problems or it will be difficult for them to enter. Simply you are blocking the path to enter through the door.That's why your are advised not to sit in front of the door.

Previously people used to live in small houses made up of wood or soil where the door used to be small, not like the door we see today. Today it is not necessary to obey the saying. But still Why we should become blockage! So if you laugh at our great ancestors then you need to understand that whatever they had said was scientifically correct. It may be not that much relevant today but still you cannot simply laugh at the traditional saying. They were more scientific than what we are today.

I know there are some superstitions which were really bad but those were either totally  banned or removed from our society. I am just explaining some facts which some people may say superstitions but actually scientific.

Keep learning.