"It would have been better to come back at the same hour," said the fox. "If, for example, you come at four o'clock in the afternoon, then at three o'clock I shall begin to be happy. I shall feel happier and happier as the hour advances. At four o'clock, I shall already be worrying and jumping about. I shall show you how happy I am! But if you come at just any time, I shall never know at what hour my heart is to be ready to greet you… One must observe the proper rites…"

I like this paragraph very much. When the fox knew the little prince will come back at accurate time every day, it will feel happier and happier as the hour advanced. It's a refined pleasure from psychology. When we are waiting for someone who we loved, the waiting time is full of worry and happiness.