I thought about this after seeing Brave. [Spoiler]

You know how the conversation with the witch went. Merida: "I want to change my mom." In the witch's head: 'did she say change her into a bear? I heard bear.' What if the witch is just crazy and turns people into bears regardless of the wish. E.g. guy: "I want to be rich." Witch: "You know what's rich? Bears."