Pushing Insanity

I've known for some time now that I need sport. Without it my body becomes sick and my mind weak. I need to push myself to the limits. I need to experience the pain and agony involved. I need to live on the edge of physical insanity. Recently I've realized this doesn't apply only to sport. I need to live on the edge of insanity in all aspects of my life. I need to push my boundaries and push some more. I won't be content with myself unless I push. I need to become the best possible person. Now I just need to find the guts to push. Where do I find them?