When the man came home, his wife was crying.
"Your mother insulted me," she sobbed.
"My mother? How could she do that when she is on vacation on the other side of the world?" the man asked.
"I know. But this morning a letter addressed to you and marked private arrived. I opened it because I was curious."
"At the end of the letter it was written: PS. Dear Diane, when you have finished reading this letter, don't forget to give it to my son."