What motivates me to learn chemistry

Ever since the first day of chemistry, I knew that this class would be difficult - From determining the amount the pressure of gas at a certain temperature to nuclear fisson.At one point, I thought that I would not pass the class because it was so difficult. But when my dad told me about becoming a doctor, he told me that I would have to work hard to become one. And that is what is currently motivating me to learn chemistry.