The Wrestler

"Have you ever seen a one trick pony in the field so happy and free?" One trick pony means he's only good at one thing. There's only one thing he can do. "Have you ever seen a one-legged dog making its way down the street?" He is making his way through life just as troubled as a dog with one leg crawling down a street "Have you ever seen a scarecrow filled with nothing but dust and wheat?" Not sure. He has nothing left to live for? Outside the fact that he puts on a show like a scarecrow he is empty inside? "Have you ever seen a one-armed man punching at nothing but the breeze?" Same analogy as the one legged dog. Punching at nothing but the breeze means he doesn't know what to do. "I come and stand at every door" He doesn't have a home. He isn't accepted, things don't work out for him.