Rumi isn't simply saying that criticism makes us better—he's suggesting something far more unsettling: that our resistance to difficulty is precisely what keeps us dull. Most people assume they need to *tolerate* friction, gritting their teeth through it, but Rumi points to something subtler: the very act of being irritated means we're fighting the process rather than surrendering to it. A parent who bristles at every correction from their teenager, or a writer who can't sit with an editor's feedback without resentment, discovers that their defensiveness becomes a thicker fog obscuring who they actually are. The polish comes not from enduring the rub, but from ceasing to flinch at it.