Just today, a stranger came to my door claiming he was here to unclog a bathroom drain. I let him into my house without verifying his identity, and not only did he repair the drain, he also took off his shoes so he wouldn’t track mud on my floors. When he was done, I gave him a piece of paper that asked my bank to give him some money. He accepted it without a second glance. At no point did he attempt to take my possessions, and at no point did I attempt the same of him. In fact, neither of us worried that the other would. My wife was also home, but it never occurred to me that he was a sexual rival and I should kill him.