Who is Ms. Muffet and Mrs. Brown from Friedman's Fables and what is their importance?

The story of Ms. Muffet, the over-controlling spider with the perfect web, is a fable about responsibility. It addresses taking too much responsibility for one aspect of life at the expense of another, perhaps more important. Mrs. Brown, whose obsession is in many ways similar to that of Ms. Muffet, suggests that at the core of such a misplacement of responsibility is a kind of delusion.