In my naivety I've never heard nor thought about "what gets measured gets gamed". It's been my intuition for a while, but it explains much of what used to frustrate me -- I wish someone had told me this 15 years ago.
What does not get measured gets ignored. It's not necessarily a bad thing to measure stuff. But it's easy to overlook a metric that later turns out to be important.
If you're measuring the wrong stuff, or measuring it in the wrong way, your metrics are again erroneous and your decisions will be based on ghosts.
Lao Tzu was truly onto something when he said "the more I learn the less I understand".