It is the imagination that gives us poetry. When you sit down to write a poem, you really don't know where you're going. If you know where you're going, the poem stinks, you probably already wrote it, and you're imitating yourself.
You have to follow where the poem leads. And it will surprise you. It will say things you didn't expect to say. And you look at the poem and you realize, "That is truly what I felt. That is truly what I saw."