To me the biggest snafu is that it's a lot easier to do the whole "I'll work for free" thing when you're 20 and have no responsibilities.
I'll also add, though, that there was a huge faith component in myself and in the startup industry that "things would just work out," and I was also miserable in school at the time, so alternatives were bleak. Having worked in the industry I've now been given a dose of reality, but having that kind of dumb faith allowed me to grow very quickly (though painfully, too), and I'm wondering how much that learned risk aversion is hurting my personal growth. That's my big takeaway from this, at least.