Artemis' favorite trait of Zoë, her loyalty. Being one of the goddess longest companions, Zoë had been with Artemis through thick and thin, never second-guessing her loyalties to her leader.
Zoë's favorite trait of Artemis was her strength. Being with the goddess for so long, Zoë had very rarely seen her act weak. She admired how strongly the moon goddess would lead her hunters, showing a less confident side only to Zoë in private.