THE JOKE

Mother : "I've just looked in the mirror, and I was surprised to see that I've got seven gray hairs!"
Tina : "But why? You are still young, Mom. Young people are not supposed to have gray hairs."
Mother : "Yes, you are right. But my gray hairs were due to your bad attitude to me. If you had been a good girl to me, I would not have had any gray hairs!"
Tina : "Gosh, Mom, then you must have been very annoying to Grandma. Her hairs are all gray!"