This kind-looking lady does not look like she would be the cause of nightmares for children the world over, but I think it has been well documented that she was. She looks like a Sunday school teacher, which she was. Or someone to have a morning cup of coffee with, which (according to the Maxwell House coffee commercials) she was.
She was a character actress for a number of years before being cast in the role that would make her famous. Although I am good at separating the actor from the role, it is still a shock when I see her in another movie. It feels like the Wicked Witch of the West is about to start trouble. I expect her to turn towards the camera and start laughing that wicked laugh.