Getting a photo of Kevin Garnett flying in the air with a basketball as he is about to make a slam dunk is another. I had taken art photography classes in high school and college. I knew how to set up a shot with subjects who did what you said. It is much harder to convince a football coach to have his team run a sweep to the right so you can get a good shot. The learning curve with sports photography is a never-ending journey of joy and frustration.
Some rolls have many great pictures.
Others have 20 or more shots that would make me wonder if I should find another line of work. Over the years I have purchased better equipment and learned more and more tricks to taking a good shot. I look at other sports photos differently and wonder how the shot was taken, with what kind of lens and at what shutter speed. When I watch sporting events I looked at the photographers taking pictures on the sidelines and envy those who have equipment that costs more than a luxury automobile. Sports photography is a constant challenge to get the great shot at whatever event you are covering.