A friend is one to whom one may pour out the contents of one's heart, chaff and grain together.
What makes friendship radical here isn't the comfort of confession itself—it's the permission granted to be *unfiltered*. Notice that chaff and grain arrive together, not in sequence: you don't sort your thoughts into acceptable and unacceptable piles before speaking, but rather spill them as they tangle in your mind. This matters because most relationships require us to be curators of ourselves, presenting only what we've already judged acceptable. Yet when your colleague admits to you (at lunch, unexpectedly) that she sabotaged herself before an important meeting because she didn't feel worthy, she's not offering carefully threshed wisdom—she's offering the heap, asking you to witness it without disgust. That kind of friend asks for nothing less than your willingness to hear the contradictions that make someone human.