Good topic. First, I have to wonder if I am really on the way of the Mustache, though I hope I am.
When I was in my mid-20s (I am now in my mid-30s), I saw a book by an early retiree called Stop working-- start living : how I retired at 36-- without winning the lottery by Dianne Nahirny and read most, if not all, of it in the bookstore. And while I was fascinated, I don't think I was convinced that I could do this too. (Or even that I wanted to do anything like it.)
Not too long thereafter, I met the man who I thought would be my partner for life. He turned out to be my partner for the next seven years (and hopefully a close friend for life) and I took a completely different turn, putting aside any idea of early retirement through frugality and saving I might have had ignited by that book. With him, I expected a more traditional path, which didn't work out.
I was re-introduced to the idea on ERE (where I got the link to ERE, I can't remember, but thank goodness I did!), but extremism doesn't resonate with me. I would list "moderation" as an important value to me. So, MMM and his mustachianism does resonate.
As to personality types, whenever I've taken a test, I've clearly and definitely come out an "I" but am right on the border for the other three letters. I think that makes me more complicated to myself because it makes it hard to have overriding values and approaches come out ahead of others; the competitors run a tight race.
I've also been influenced by my mother, who was born the youngest of 8 kids at the end of the depression. Her first memories are of war-time rationing. Being the youngest, she was influenced by older siblings and an older mother of, perhaps, an older generation than the mothers of most of the kids her age. In turn, she had me at an older age, so I seem to be quite a bit off in terms of the number of generations for whom frugality hasn't been the way of life (read: I am the first generation who was raised in a manner where frugality became a choice rather than the given way). She also very much values retirement, having retired from teaching with a full pension at age 55 and, now, over 15 years later still believing it has been the best phase of her life. She is someone who enjoys relaxation and a slower pace of life than typically takes place when one works full-time.
I lived without many extras I would have liked for several years when I was a student. The worst of it was the combination of not having a car nor any laundry facilities in the building where I lived. I also didn't have cable or a dishwasher. These are all things that I now have and that I really enjoy having and don't want to go without. That along with enough living space to not feel claustrophobic. I don't want to go back to that lifestyle willingly, though, admittedly, it might work just fine if I didn't also have to swing it with full-time work or studies; finding time to wash dishes by hand and go to the laundromat might not seem like such a challenge if none of my time was swallowed up with paid employment.
So, having no immediate plans to drop cable TV, I may or may not be mustachian. But I am excited about putting some little soldiers to work for me and perhaps knocking some years off my retirement date or, at least, having the financial means of retiring sooner than anticipated if I so choose.
