"I have always felt that I've needed to prove myself." That's Stephanie Unwin, who became the CEO of Veronica Beard this year after thirteen years as its president. Most of the leaders I coach feel the same way. They get the title or build the company, and a few weeks later they're already chasing the next thing. I did it too. I spent most of my career trying to show my parents, and then everyone else, that I was worth something, and I still catch myself doing it.

I don’t believe in New Year’s resolutions; they often feel fleeting and tied to arbitrary deadlines. However, I deeply value the practice...