Although patriotic, I am neutral about sports, but not Chris, who happens to be Canadian. He was so happy about Canada winning both hockey gold medals that if I could have my way, it would happen once a day.
As an exercise:
Does your main character care about sports? What other external events that are not directly personal affect your main character? Politics? Fashion? How does this shape their behavior? Where did their love of this subject come from? Their hometown? Their parents? Is it an everyday thing or does it just interest them every four years?