I can't wrap my head around it...

The other day as an older guy I play soccer with was driving us home he was asking how the training was going. I gave him a generic answer; "Fine. The hours are long but I'm feeling pretty good." He proceeded to ask why on earth anyone would ever want to do such an event. I started supplying a string of answers, none of which were satisfactory to him. He kept saying, "I just can't wrap my head around it..."

I simply replied, "If I can do this here, I can do anything. Really. If I can train for a triathlon in a place that is not designed for or friendly towards bikers, runners or swimmers then I truly can do anything. Nothing will ever be this hard again."