Kids Will Be Kids!
Published Jan 01, 1900

A six-year-old comes crying to his mother because his little sister pulled his hair.
"Don't be angry," the mother says, "Your little sister doesn't realize that pulling hair hurts."
A short while later, there's more crying, and the mother goes to investigate.
This time the sister is bawling and her brother says, "She knows now."
Originally published November 14, 2002.