An executive went away on a long business trip. Before he left he asked his secretary to forward all of his mail. However, he forgot to give her the key to his mailbox. When he realized his mistake, he mailed the key to his office so the secretary could send his mail to him. But, she never did mail it. The executive got angry and phoned his office, planning to fire his secretary. However, she was able to explain to him why she hadn't sent his mail. He quickly realized he was in the wrong and apologized. What did the secretary say to make the executive realize his error?