The common warning given which applies to more than just crypto is "Don't invest more than you can afford to lose." which is a good axiom, but one will only "lose" it if they are scammed, if they make some kind of avoidable mistake, or if they sell when they are down.
For me, it boils down to "don't invest more than you can afford to forget about", which in certain ways is saying the same thing, that this is money that shouldn't be relied on for living expenses. But I think this phasing sets a better expectation.
If you sold at the dip, was it because the money was needed? If so, then it was too much to begin with.
If you didn't sell out of necessity, did you sell because of fear/doubt? I guess that just depends on what timeframe and strategy one is employing. If you believe in the tech, and understand it enough to believe in it, then it might make it easier to go through the dips and even the flash crashes.
If the onus of investor protection is still on the investors themselves, one needs some degree of technical literacy to sort away the fools gold.
But there are also cases where good faith developers may get ahead of themselves in terms of concept, and base too much of the value proposition on potential future developments, rather than what exists and what works at the moment.