This is one I can answer and, since it actually reflects my Mustachian story, my first post.
Harvard grad, big firm for a number of years, and now government for about 7 years. I am a happy Mustachios lawyer, mainly because I stopped living like a lawyer, and know that as a result, I only have a few more years to work.
The back story. At the firm, I was unhappy most of the time working long hours (and, really, unhappy working much at all). The pay was great, but what I saw was that most people were miserable, and I often found myself spending money as a reward for suffering through the day. In a sense, it felt like all I had to show for a crappy 12-14 hours was money, so I might as well spend it.
Then I went to the government and took a 2/3 pay cut. But the hours were much better, and despite still never really being a worker bee, I mostly enjoyed the job and found myself working a regular schedule and getting to spend a lot of time with my family and working out. We cut way back on our expenses, but didn't pay too much attention to finances because we made more than we spent and didn't have much debt, so I felt like a financial success.
About a year ago, MMM turned my world upside down, and completely for the better! First, I realized that it was okay not to work all my life. It sounds weird that that should be surprising, but law feels very much like a career profession. Of course, I spoke to lawyers who fantasized about walking away from it all as a break from the stress and hours, but not as an actual plan. After reading MMM, I could finally admit that although I have a very good law job, I don't really enjoy working to work. The idea of building a resume, making sure there were no gaps, etc., was someone else's ideal. I need enough money to be financially independent, and that's it.
Second, MMM forced me to focus on my finances. I did my first budget and was proud that I expected to be net positive $798 for the year! I laugh now because after a little less than a year of cuts, my net-positive number is over $100,000. The secret? I realized that I bought a lot of things because I could, and really, to reward myself for getting through work. Once I realized that I didn't have to work forever, each dollar I saved got me closer to freedom. And what was interesting was that once the stress of having to work all my life went away, I started enjoying work more and enjoying the things I already had. I don't need to regularly eat out for lunch or dinner, I don't need fancy clothes, I don't need a fancy car, and I don't need to have cool electronics and other stuff. I spend my time riding my bike or running, ride to work most days with my wife and kids, and generally work regular hours unless I'm in trial. People joke that I no longer look or act like a lawyer, and that is totally okay for me.
Third, I realized that my happiness is up to me. Most lawyers I've met are stressed on a fairly regular basis. The hours and workload are often intense, but there's a sense that it's not something that can ever be given up. For me, I've decided that yes it can. Nobody will care whether I was a lawyer for 20 years (my current retirement goal) or 40 years, and I'd much rather be the 20-year lawyer.
So I'm thankful for MMM and the Mustachian ideals. Lawyers get paid more than most for the skill and often stress our jobs require. Taking advantage of that pay to get to FI more quickly is one of the great possible benefits. So yes, I'm a Mustachian lawyer for now, and happily so. But that's because I'm only going to do it as long as I have to, then off to Jimmy Johns to get paid to ride my bike!