Sleep and food are not the only resources which need to be replenished. Whatever powers your day, be it willpower or creativity, needs to be charged as well. We often treat willpower like an unlimited resource despite science clearly showing that we have less willpower after our willpower has been used. Creativity is not necessarily the same as willpower however the building blocks still need to be in place, for creativity to renew itself: exposure to new ideas, sharing them, extending and modifying them. Make sure to charge yourself up, because there is really no reason to treat your iPhone better than you treat yourself.