The runner mentality

I'm back from a visit to Green Bay, where I went to cheer my sister on in her first marathon. It was awfully chilly, but there were a ton of people there, and she did a really good job. When she finished, she asked me if it had inspired me to run a marathon. My answer: "no". I don't really get the runner mentality. Even if I was in the shape that I could run a marathon, I'm not sure why I would want to. I have a car. I don't need to run from any large predators. I don't need to urgently deliver a message to the next village. I still think it is a very impressive feat and am amazed by those that accomplish it, but it just isn't for me.