Poets are constantly crippled, creatively. It's the way it works. You write a line and, just now, right now, it seems like it's the best line in the world to date. It's a shiny, beautiful line, a thought, an image so remarkably profound that you are in awe of yourself, or (if you are a seasoned poet) in awe of that angelic being which sits on high in your mind and occasionally drops little scraps of poetic manna into your head. Now, you only need to write a poem around it.
Because the poem takes over, sprouts a million legs and scurries in directions you had no real intention of it going and now the Wondrous Line of Glory and Poetic Win doesn't fit. You have to either change it or take it out and save it for another poem. Or make it a haiku-like short poem on its own, so all those other words don't assault it again. If you're an experienced poet, you'll probably just store it in a .txt file or on a post-it note somewhere and lament it until you're old and nothing matte