Of all the phobias on this list, pentheraphobia is probably the most common. It is, as stated above, the fear of one’s mother-in-law. I am sure that most married people have, at one time or another, suffered from this terrible fear. This fear is one that is so common in Western society that it frequently appears in movies and other forms of entertainment. Of the many available therapies for this illness of the mind, divorce seems to be the most popular. A related phobia to pentheraphobia is novercaphobia which is a fear of your stepmother – the most famous sufferer of which is Cinderella.