From the video:
I have three muscles, without which I couldn’t do my work. The first is curiosity. (You can call it inquisitiveness, you can call it questioning.) The second muscle [is] the muscle of appreciation. It’s not questioning so much as it is noticing… how joyful things can be, how colorful things can be, what already exists as an inspiration. The muscle of curiosity and the muscle of appreciation enable the muscle of imagination.