For writers caught up in the throes of creative passion, everyday matters like personal hygiene can seem frivolous and incidental. A lot of writers I know never bother to get dressed in the morning, especially on those days when they wake up with a great scene already forming in their minds. Sometime between lunch and dinner they might realize that, not only are they still in their pajamas, they also haven't showered in three days, which could explain why the dog has suddenly grown so fond of the backyard. When there are so many dishes stacked up in the sink that you're eating your breakfast cereal with the gravy spoon, when you're down to wearing last year's bathing suit bottoms because you're out of clean underwear, or when the dog who's grown so enamored of the backyard can walk through the grass like a barber parting hair or Moses splitting the Red Sea, well, then you know you're onto a really hot story. Of course, not every writer considers an empty fridge a minor irritation or thinks that flossing is a waste of precious writing time.
Some writers have normal, decent personal habits.
They eat well-balanced meals, get regular aerobic exercise and not only wash and dress in the morning but actually put on makeup. A few of them are even successful. I suppose the situation isn't completely hopeless. I, myself, once swore I was going to reform. But that's another story and will have to wait.