I put in a lot of work (although far short of putting my actual life on the line) to get the qualifications I have -- but it didn't feel much like work at the time, because it was something I found fascinating and intrinsically rewarding. THAT'S the part where I got lucky: having a hobby/interest/whatever that people would pay me to do, and having the gifts of genetics and upbringing to be able to do it well. If I'd been born with a brain that dedicated the usual space to names and faces and social connections, instead of patterns and math and trivia, I'd probably be in a very different place today. If I'd been born to parents who scoffed at "book larnin'", or who got drunk every night instead of reading to me or helping me with homework, same thing. If I had the drive to work at it during all my waking hours, instead of being distracted by stories or TV or (ahem) present company, I'd probably have achieved more by now -- more "success", more fame, more power, more money. I might even be happier. But that's not who I turned out to be, and I don't especially want to remake myself into that person right now, so here I am -- happy, mostly, and financially comfortable.
I chose my profession based its ability to provide a good living (in demand, semi-decent security and salary, not requiring super long hours). It was not my passion nor was it my natural talent at the time. I believe I could have learned to enjoy/love a number of different types of professional careers. However in the end I think happiness is elusive and find more peace in having made a difference.