What were your biggest lessons (from losses) in crypto?

Saw this question on another sub and got curious to ask peeps here: What did you have to learn the hard way in the crypto space?

In a somewhat "bull run" it's hard to talk about bad things, but it's always good to have some perspective: Were you rug-pulled? Lost money margin trading? Trusted some huge APY on a DeFi protocol only to discover the base token price was going down the drain? Got scammed by somebody offering crypto support?

My case: Bitmex was my biggest lesson not to f*ck with margin trading unless you 110% know what you're doing, or if you are an insider.

I lost a lot of money on Bitmex in the past bull run because I was feeling greedy, and I would be much more wealthy today hadn't I been so reckless about it.

What's yours?