My daughter-in-law, Sarah, has always had a competitive streak, but she usually hides it behind a thin veil of “hostess with the mostest” perfectionism. When she invited me to her big 4th of July bash, she was unusually insistent about one thing.

“Don’t bring anything,” she said over the phone, her voice sugary sweet. “If you show up with food, I’ll be offended. I want you to just be a guest for once.”