Yes, I have.
15-18 I was working for a psychiatric hospital as a peer counselor and later a tech. I was still in high school, but worked part time during school, and full time over summers and breaks. I was going to go into psychology, and eventually psychiatry, but crashed emotionally by the time I was 18 and didn't want to do it for work. I still volunteer at times. In hindsight, I was really young with a lot of responsibility - 16 years old with a pager and on call.
18-24 I was in college and law school. Couple business concentrations (econ., finance) and interned at various financial institutions, then I clerked for a large law firm downtown during law school. A number of things led me away from law; had a few regrets at first, but absolutely none at this point. Law school was interesting; my thoughts are really bi-polar with law school.
25 - present I work in finance. I really like it and enjoy it, albeit I know that this not my calling - I need some direct meaning behind my work. I also have some disdain with the culture of finance (imagine a modern version of Wall Street with Gekko clones), and this is not just specific to my firm. Taking pre-med coursework at night and will apply to medical school within a couple of years. Volunteering as time permits. I have a couple of ideas of where I want to go with it, but I still have time to decide on an exact plan.
LBYM all the way here; no school debts. I never really struggled with the work itself, but moreso adapting to new cultures and new ways of approaching work.