A young man went to consult a
          doctor. "What is your problem?" the
          doctor asked. "That's your problem!" the
          man retorted. "If I knew what my problem
          is, I would not have come to you! You are
          the one who should know what my
          problem is!" "Well, in that case, will you
          please wait outside? I will attend to you in
          about an hour," said the doctor. "Why?"
          asked the young man. "Because I have to
          call a veterinarian to come to help," replied
          the doctor. "Only a vet can diagnose his
          patients without having them explain!"