Andrew was standing in a bus stop. A very attractive woman came from behind and said, "Hello!" Her face was beaming. He gave her that "who are you look," not remembering ever having seen her before. Noticing his look, she figured she had made a mistake and apologized. "Look," she said "I'm really sorry, but when I first saw you, I thought you were the father of one of my children," and walked out to board a school bus.
Andrew was dumbfounded and thought to himself, "What the hell is the world coming to? Here is an attractive woman who can't keep track of who fathers her children!" Then, he was happy that he might resemble one of her former lovers. Suddenly, he got a little panicky when and thought, "May be during one of the wild parties he had been to, when he was in college, he did father her child!
He boarded that bus, holding his head in his hands, never realizing that she was his son's teacher.