What defines poetry (Caferati exercise)

We hear these often:
"What makes a piece of writing a poem?"
"Those are just prose sentences with weird line breaks."
"I don't know anything about poetry."
"That's really poetic!"
"It's all about self-expression. I write from within my heart."
"I never edit my original poem. That would destroy the sacred words that marked a divine moment."
And so on.

So let's hear it from you. What is poetry to you?

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I have the same take on poetry as art. No one seems to be able to define what art is, nor what poetry is. So we must accept that everything is art - from your kid's crayon masterpiece to Van Gogh. Maybe it's the process that is art, not the end-point. Maybe that's the same with poetry.

But greatness, that is a different matter. I think most people are aware of the distinction between art and great art.
I'm obsessed with greatness. Great art or poetry is very dense in content, that much is for sure. What bothers me about some Caferati poetry is the unbearable lightness. Yet, it is so very very hard to create anything great, one cannot fault them for it.