Having been away from my little sister for a few years, I was surprised to find that she was not a morning person. Our family had always been early risers, so it annoyed me to watch her stumbling around the kitchenette trying to figure out how to make coffee in the tiny pot the condo provided. I eventually shoved her to the side and made it for her.

“I hope this is strong,” she said as she blew across her mug.

“I thought we’d be leaving by now.” I paced back and...