They are the only people allowed in my office when I'm writing. Lucky seems to understand that. He growls at my wife or my daughter if they try to enter. Maybe he senses me growling on the inside. I don't like being interrupted.
Writing is a kind of self-hypnosis.
Interruptions break the spell, and it's sometimes hard to get back. I generally write for about two hours a day, the first thing every morning. After two hours I find myself losing energy and concentration. It's best to quit while I'm still excited about the story. Then it will be easier to get started tomorrow.