That one is so true.
When I was younger I came home one day and my mother said, "I think there is a letter from your school for you on the table." I looked at the letter and asked my mother how did the post office manage to get delivered to the house. She didn't understand the questions so I showed her the envelope.
She had opened the letter, read it, and then re-sealed it. The problem was that she put the letter in backwards so the address was no longer in the window of the envelope.