The story is told of Dr. Charles Mayo who, with his father and brother, founded the world-famous Mayo Clinic. A group of European medical experts was visiting the clinic and were staying as guests of Dr. Mayo at his home. In their own countries it was the custom of these gentlemen to place their shoes outside the bedroom doors for a servant to polish.
As Dr. Mayo was retiring he noticed shoes lined up outside the rooms of his guests, but it was too late to wake any of the servants. With a sigh he picked up all of the shoes, hauled them to the kitchen, and spent half of the night polishing them. Dr. Charles Mayo was secure enough to be humble himself like that.
Jesus was secure enough in his relationship with his Father to humble himself to wash his disciples' feet. He had no need to say to the world, "Look at me! I'm somebody great!" He had all of the approval he needed.
Note: A rather harmless story but we were not able to confirm the events.