A very good question: WHY is Peyton Manning so good?

I think this is a great question. We all see Peyton in action and see his great plays...... But why is he so exceptional? What makes him so memorable? No matter what game you are watching, you are going to hear about Peyton's greatness. I swear, every game I watch involves Peyton being brought up. I don't disagree with people celebrating him, but I do wonder about why he is so great. Do you have a good answer?