Is there a specific person that you knew, or know that inspires you in your riding? It can be a friend, a family member or even a rider you admire.
Mine is definitely my grandfather, even though I never really knew him (he passed away when I was two). In his younger days, he was a very good show jumper, and apparently he always told my mother and grandmother about his show jumping days.
Whenever things get tough, I think of my grandfather, and of how I'd like to be a jumper like him.