My answer (with possibles grammar mistakes, but I am Alsatian, not English):
Concerning what to do in life, it is indeed especially difficult for me to give advices, because I never had myself to ask this question, having decided at 6 years old to become a chemical physicist (at that time, I said "chemist", but I know that this word was wrong, for describing what I had in mind).
Anyway, even if the first 20 years of my career (a word that I don't understand really) were scientific publishing and not full time chemical physics, I was very happy there... otherwise, I would have changed immediately. Indeed, I found my job interesting, because I felt that it was useful.
By the way, was it really "interesting"? And is chemical physics interesting ? I propose that these questions mean nothing. This is like for food: only children say the "I like" (sweets, for example) or "I don't like" (spinaches, for example); later in life, they like all what is edible.
My job then and my job now are the most important things on this earth because I decided that they are important, that they are interesting, that they are "good". And with bad faith, I find all possible reasons to explain that these activities are the most beautiful.
When I was working as a scientific publisher, for example, I felt that I was doing something politically useful (whereas I was doing my science in my own lab, at home, during week ends and holidays), and I was already saying that this was wonderful. And because it was decided that this was "interesting", I was doing it extensively! And extensively means successful, of course: labor improbus omnia vincit, a thoroug work is always successful, said the Romans.
But coming back to job choices, I propose that we don't remain with phantasms, and that we consider the real, practical work involved. What are the tasks to be done, second by second, from when you put you foot in the office/lab/xxx up to the end of the day ? This is very important. For sure, some people have the feeling that they have to stop in the evening or during week ends, but is this really necessary, if you do what you have to do, if you do what you like (love) most in life ?
Another analytical grid for evaluating possibilities, when you have the choice, is "intrinsec interest/extrinsic interest/concommitant interest", i.e. how you are interested, how much you get, social environment... But of course, again, the "intrinsic" is discutable, as you can learn to like or love something, and I don't like the idea of preferences falling from the heaven (his is for simple minds).