Breaking Your "Four Minute Mile"

I ran across this article while browsing today, and I thought the story behind it was quite good (and the article a bit motivational).

I have always held the belief that you should question "conventional wisdom" and strive for the Beyond. You either learn that the wisdom was correct or that circumstances have changed enough that you have a real innovation. We place psychological barriers in our way all the time; we should keep a vigil eye towards breaking down those assumptions.