I discovered bitcoin when it was about $5 per coin and during that time for several reasons I could not buy it. I discovered eth and xmr when they were around $10 per coin and I could not find a good place to buy them. I discovered netko when it was about $0.05 and I could not get the wallet compiled. I probably had around 40 bitcoins and cashed them all out under $800 and I could name more.
You?
The biggest regret I have made in cryptocurrency is when I keep on holding a token being greedy that it will keep on mooning. And as a effect of greediness, the project shut down and the token I hold for a long time have no value now.