When I was younger, I liked working in software. It was fun, and interesting, but did I "love" it? Honestly I don't think so.
Looking back on my time as a student, I can't think of any subject that I loved so much that that studying was something I wanted to do. It was always a chore, always something I did because it was a means to getting to a point in life where I didn't have to do it anymore.
Now, at halfway through my 50s, I would not be able to answer the standard interview question "what are you passionate about?" Nothing comes to mind. Everything I do day-to-day is either stuff that I need to do to pay the bills and support my family, or is in some way procrastinating on stuff that isn't yet so urgent that I have to do it.
I think people like Feynman are born with a burning passion for learning that most people just don't have.