It's a tough premise, that I'm sure a lot of us struggle with.
I'm of the opinion that you don't have to love your job. I'm in a field that I generally like (computers/technology) doing an inane job (to me) making good money, so that I can spend the rest of my life enjoying what I do 24/7.
I think that if I had the choice between living my current lifestyle, doing a job that I don't quite like, and "retiring" around 40... or living my current lifestyle, doing a job that I LOVE, and retiring at 60+... I'm not entirely sure what I'd choose.