The number of miles I have run since I was a toddler would have taken me around the world several times, and I still cannot define precisely my joy in running. There is no sacrifice in it. I lead what I regard a normal life. In my case, I thoroughly enjoy running 100-odd miles a week. If I didn't I wouldn't do it. Who can define happiness? To some, happiness is a warm puppy or a glass of cold beer. To me, happiness is running in the hills with my mates around me.