Two very close friends, Karen and Sophie, went on a long-awaited vacation to a tropical island where, the first day, before that evening’s grand welcoming luau, they spent the whole day playing in the ocean.

But early on that same evening, in the midst of all the great food and fantastic island music, Karen could barely keep her eyes open. Every part of her felt tired; in truth, she was feeling a bit of resentment towards her friend. For some reason, Sophie was showing no sign of slowing down, while all Sally wanted to do was to just collapse somewhere. It just didn’t seem right!

So, collecting her thoughts—as well as her facial expression to not show any of the irritation she was feeling inside—Karen pulled Sophie aside and said, “I don’t get it. You and I did the same thing all day: we lay on the beach and swam in the sea. Why aren’t you as tired as I am? How come you seem to have energy to spare, and I’m dead in the water?”

“Well,” said Sophie, “all I can think of is that while we were out playing around in the surf—which was for most the day—I enjoyed floating quietly between each of the waves and you—well, you didn’t.”