This is something I've struggled with a lot. Right now, I'm FI, but not RE, for a couple of reasons:
1) The work is easy; not demanding, no office politics, not the 'drudgery' I was taught it would be as a child.
2) I'm my own boss. OK, my customers are my boss, but they're easy to work with.
3) The money is fantastic.
4) How else would I spend my day(s)?
5) I love the thrill of closing a deal/sales.
6) I pretty much do what I want now anyways.
To elaborate on #4: When I was in my 20's, I spent a year and a half traveling the world on a shoestring budget. Hitchhiking across southern Africa, seeing the Middle East, Southern and Eastern Europe. It was a blast and it changed my life for the better in many, many ways. One thing I learned was that, believe it or not, there comes a time where you don't want to see another amazing Roman ruin, spend the night in a cool castle, enjoy the best views of the city, climb a mountain, see more elephants/gazelles/giraffes/crocodiles/hippos (etc.) or spend (another *f'n*) day at the beach. .. ... because there's no point to it. It took me 18 months to reach this point in my exuberant 20's. Now I might reach that point sooner.