The famous American writer Mark Twain was well-known for his absent-mindedness.
One day, while traveling by train, the conductor asked him for his ticket.
Mark Twain searched through all his pockets but couldn't find it. Recognizing the writer, the conductor kindly said, "It doesn't matter. You can show me your ticket on your return trip. If you can't find it then, it's no trouble at all."
"Oh, but I must find the damned thing," replied Twain, "otherwise how will I know where I'm going?"