Why did Magdalena use her hair to dry Jesus' feet?

I don't really understand this part of the story in Luke 7:38. Why would Mary Magdalena use her hair to dry Jesus' feet? I have some clues, but I don't want to guide the replies. I'd like to know both, the symbolism, and the spiritual meaning (what does it teach to us). >As she stood behind him at his feet weeping, she began to wet his feet with her tears. Then she wiped them with her hair, kissed them and poured perfume on them. > >(NIV) .