I've clung to the belief for years that there must exist some magic formulas that can reliably, massively outperform the market. Thus I had an investment adviser with a 1.5% fee who could match me up to fund managers with another 1.5% fee and a wondrous graph of back-tested, market-crushing results. We would then throw money at said manager where it would either grow smaller or not grow for a few years before finding a new manager with a new wondrous graph.
Today I finally closed the last of those expensive, complicated, volatile and under-performing funds! I've also been building up a more traditional low-fee array of investments aside of this nonsense, but about 6 months ago I go serious about a consistent asset allocation using Vanguard funds. It feels much better to base my FIRE on a sensible, realistic strategy rather than snake oil.
What finally sparked the change was reading - don't laugh - Tony Robbins' "Money: Master the Game", where he promised to reveal an investment strategy that averaged 9% returns with only 3 down years in the last 40. It turned out that his allocation was a little heavier in government bonds than I'd like, but it opened my eyes to the fact that asset allocation strategies really have matched most of the returns of the s&p 500 with reduced volatility (no guarantee of future performance :). Much of Robbins' other advice is really quite sound, some of it inspirational, but overall mostly common sense.