Isn't it true? We love to root for the underdog. There is something that is heartwarming, that moves us to see people who are managing with a liability, disability or are going it alone. We want to reach out and elevate them; help them reach new heights and realize their dreams. And even if we can't help them, we applaude their unexpected achievements. We celebrate their hard fought successes.
I think "the underdog" reminds us of our own frailities and insecurities. When we witness obstacles being overcome, ceilings being smashed -- the possible made possible -- we are filled with hope. Our own sense of "anything is possible" is validated.
So I guess you could say that when we are cheering on the underdog, we are cheering on a part of ourselves. Make sense?
PS -- Inspiration for the post -- I was just watching Dancing with the Stars ...