why does Juana feel that it is not good to want a thing to much

Juana, like many in her village, is superstitious. She believes that the Gods do not like vanity in people. The Gods give and take away as they please. They do not like individuals to drive their own destiny, “It is not good to want a thing too much,” she muses. “It sometimes drives the luck away. You must want it just enough, and you must be very tactful with God or the gods.”