Have a heart
Today, I had to jog quickly across a large piece of property and back while my wife and kids walked to the car. When I met them at the car, I could feel my heart beating, but I only needed to take an occasional deep breath through my nose. It hardly phased me.
On the way home in the car, I got to thinking: most of the benefits of cycling are tied into my circulatory system. It's my heart and blood vessles that make it possible for me to endure.
I respect people who've got great outward muscle development, especially in their upper body. But what really counts is the part you can't see on the outside: the development of the "inward transportation system," the heart and blood vessels.
I am so grateful for what I've got. It just motivates me to keep riding.