What's on your "To Don't" list?

I once watched a highly energetic chief ripped asunder by a senior member of his board. “Richard,” the determined board member almost shouted, “you are smart, energetic, creative to a fault, perhaps even a genius. But much of your 'genius' is dissipated because you apply it to ten different things at a time, albeit with great skill.

“Let me tell you what you need,” he concluded. “A 'to don't' list.”

I don't know about “Richard,” but for me that was a profound moment. Fact No. 1: We all have 50 genuine priorities. Fact No. 2: If we get even two Big Things Done in a six-year tenure on the current job, we will have had a...Great Ride. Axiom No. 1: Therefore, what we choose not to do (the sole subject of that “To Don't” list) is at least as important, or more important, as what we choose to do.

And, finally, effective “To Don't-ing” is far, far more difficult than effective “To Do-ing.”