That is the Quote of the Day.
It gets to the heart of the issue I am raising. I was responding to a promotional video that hired a celebrity to speak a bumper sticker aphorism.
We can be defined by our thoughts, and most people allow that to happen to them, and worse allow external forces to determine their thoughts, allowing themselves to be defined by others. I agree with those philosophers who say that we always define ourselves. Even letting others define is the act of letting others define us.
As a loose Daoist, I do love the idea of emptiness, interpreted as not clinging to preconceptions and negative judgements but being openness to new ideas and the lightness of Being. Thoughts come, emotions come, we can decide what we do with them, we need not be filled and defined by them.