Well just try not to become a tin man: The Tin Man
"Something not to be overlooked about the Tin Man is how he is made of impenetrable metal, not flesh. This is a powerful symbol, meant to draw your attention to something important about this character. When Catalysts get emotionally injured, they tend to erect psychological "barriers" to avoid suffering further damage. It's a completely understandable reaction. The paradox is that the same barriers which protect them from getting wounded will also act as barriers that inadvertently preclude them from feeling loved."