Kellee (Talks about what the job of booking models taught her): When I walk into a room, what does the person on the other side of the desk actually see or feel? How can I make that impact? she said (who, if she ever quits acting, might want to consider motivational speaking).
I learned that good is never good enough, that you have to come out feeling like you did the most amazing work possible.
Because then you've won that challenge for yourself, and whether or not you get the job will not affect you negatively in the same way.