Does the near term prospects of FIRE / early retirement predispose mustachians to shorter term thinking, chasing returns, speculation and gambling?
Or does an interest in FIRE preselect for people who tend to question default assumptions?
Sometimes that produces positive outcomes: "No one can afford to retire before 70? Why? What are the numbers behind that?" "So I know I cannot get money out of my 401k before 55 without paying a penalty, but if I convert the money like this, and what X years... doesn't that get around the law?"
Sometimes it produces negative outcomes. It sounds like the MMM (both the author and the community's) experiment with Lending Club and peer to peer lending generally may have turned out be in this category but I'm not convinced this could have been confidently predicted without testing first. And the reports from people who have tried P2P lending have been really helpful in convincing me that it
isn't a good investment at this point, which I wouldn't have gotten just from reading recent public coverage of the industry.
The majority of assumptions are assumptions for very good reasons. But if you're not willing to -- carefully, with contingency plans* -- tests assumptions from time to time you won't identify the cases where the assumptions are false/misleading/activity harmful. Most folks on this board who haven't FIREd yet are in a good position to test their assumptions about investments now, because they generally are saving large sums every month, and a well planned failed experiment might cost them a few weeks or a month or two of extra work, but won't imperil their retirement.
*Let's take the discussion in the 2-3 cryptocurrency threads as a good example. Most of MMM the folks I've seen talk about putting money into either cryptocurrencies or mining are proceeding cautiously, with money they could afford to lose and not delay FIRE significantly. It may accelerate their FIRE date a bit, it may slow it a little, but it won't be a catastrophe even if it goes to zero (just like, hopefully, no one is going to be wiped out by the decline of peer to peer lending).
Now to be fair, I've seen two posts in those that raised some big red flags for me. One person was trying to figure out how to put more than $10k/week into bitcoin, and another commented on having 80% of their networth in cryptocurrencies. I wouldn't describe either of those as testing investment assumptions
carefully.