During the period of post-collegiate aimlessness which afflicts many young people possessed of a brand-new undergraduate degree with no immediate, practical real world value and no idea what to do with their lives, I spent six months participating in a work exchange program, working in a bookstore in London. It was a great experience which I highly recommend . . . but that’s not the point.

The store where I worked wasn’t one of those charming, idiosyncratic, Charing Cross Road types, evoking dusty tomes, hidden gems and tales of long-lost love. It was a branch of a local chain of bookstores, located in the City, the heart of the banking district. Picture the area where the father in Mary Poppins worked, if that helps. Very gray, lots of tall buildings. As a result, we didn’t get many tourists there, just businessfolk on their lunch breaks. And conversely, our customers expected it to be a Yank-free zone.

One quiet afternoon, I was working the cash register at the rear of the store. A businesswoman in professional attire purchased a copy of The Hitchhiker’s Guide to the Galaxy. The minute I opened my mouth, I was busted. “You’re an American!” she said in a disapproving tone. I acknowledged that I was. She asked if I’d read the book, and I said that I had. The customer gave me a long, dubious look, then said, “Well, did you get it? Because the humor’s quite British, you know. Subtle. Nothing like yours.”

I assured  …