I was walking down the street when I was approached by an eleven- or twelve-year-old boy. He introduced himself and said that he was selling tickets to the annual Boy Scouts circus to be held on the upcoming Saturday night. He asked if I wished to buy any at five dollars apiece. Since one of the last places I wanted to send Saturday evening was with the Boy Scouts, I declined. “Well,” he said, “if you don’t want to buy any tickets, how about buying some of our big chocolate bars? They’re only a dollar each.” I bought a couple and, right away, realised that something noteworthy had happened. I know that to be the case because: (a) I do not like chocolate bars; (b) I do like dollars; (c) I was standing there with two of his chocolate bars; and (d) he was walking away with two of my dollars.