She describes how David is such a pusher. While running, Kathryn will gain some perspective from listening to Goggins’ audiobook. She mentions the cookie jar, which is a metaphor of your accomplishments.

Every time you’re proud of something, you’ll put an imaginary cookie in the jar. When you have to do something that’s really challenging, you’ll pull the metaphorical cookie out as a reminder and motivator of the previous things you’ve accomplished, and you'll push yourself to accomplish the next challenging obstacle.