How White Hairs Come to Be

One day, a little girl is sitting and watching her mother do the dishes
at the kitchen sink. She notices that her mother has a few white hairs.
"Why are some of your hairs white, Mom?" she asks.

Her mother replies, "Every time you do something wrong, one of my hairs
turns white."

The little girl thinks about this for a moment, then asks, "So how come
ALL of Grandma's hairs are white?"