Shared Understanding

Everyone should have dinner with my parents. It's an experience all its own. It starts with talking to each of them as individuals, because they may be totally unlike what you would expect. Then you realize that these two people are married to each other. And finally, you realize that these are the people who raised me, and that I have become the person I am because of them.

Once you have had dinner with my parents, you and I will have a shared understanding. We both know these people, what it's like to be in their presence, the things they know, the things they talk about, and it will allow us to communicate more easily. I will never have to explain certain aspects about my parents because you have already witnessed them.

The writer/reader relationship heavily depends on shared understandings. If people are not on the same level, communication will be flawed. If you write about something that somebody doesn't understand, they will be confused. If you try to explain a subject that the reader already understands, they will be bored.

This is why it matters who your intended audience is. This is why you can't please everybody. Different people share different understandings. You have to pick the group of people that does or does not know about a subject, and write in a way that best communicates with them.