my biggest regret in crypto is the fact that i didn't buy and store enough ETH early this year when it went as low as below 150$. And i even sold the little i had at about 200$ now i am regretting .
this is most of holders regret. no one knows the price will rise or down in the near future.
btw, my regret is when i invested my money in shitcoins and scam ICOs in the past. even they look like a good project. that's why i am investing my money on BTC and ETH only now. i don't believe any altcoins for now.