a) By working in different environments they slowly realise that they're good or bad at that thing, and so they realize their abilities.
b) By working on something you love, you overcome obstacles and you slowly achieve your goals in life by being happy and productive.
c) I disagree with this one, by putting heart and soul in the work you do, you will make better work than if you wouldn't put heart and soul in the work you do because you will be distracted and make more mistakes.