From a conversation with Claudia Rankine: "What makes a great poem great, and what makes a bad poem bad?"
I think the great poems for me are ones that take me to a place that I recognize intuitively but didn't know. There's a vast chasm between knowing something and knowing something. And the great poems, they're so familiar that they're unfamiliar.
A bad poem, for me, is if I read a line, or two lines, and you know what the next line is. You see the world of it, before it sees itself. The minute that happens, it's already done. It's finished.