Regret is an inevitable state of mind in crypto at one point or another:-
why didn't I buy that coin when it was $0.50?
why did I sell this coin early?
why didn't I take profits on the way up, only to see the value fall 50% in a market crash? (a lot of us in the last crash!)
why didn't I buy the dip?
why did I FOMO and buy at the ATH and now I'm holding an unrealised loss?
why didn't I buy more of this coin?
We're all going to make "mistakes" that lead to a feeling of regret and self-admonishment.
I have a couple of strategies here to help me dampen the feeling of regret.
1. I have to realise that regret is largely based on a "maximalist"/perfectionist mindset, which is both unrealistic and unhealthy. We are attached to the notion of maximising profits. But what would that involve? It would involve being the perfect, machine-like investor. Always buying low, selling at an ATH, taking profits at the perfect time. It's an impossible standard to live up to.
If I make a profit, I compare my profits to the stock market. If you do THAT, realise you're likely "killing it" even with a "modest" 100% gain (it's ridiculous even to put "modest" here). If you can make a 10% gain a YEAR in the stock market, that's considered a success.
Also realise that the maximalist attitude is largely shaped around only hearing one side of the story of other people's trades. People boast when they're winning, and they're quiet when they're losing. Therefore, you can start to think that everyone's doing incredibly well.
2. I can only compare myself to the other me who didn't get into cryptos at all. That's your baseline to compare to. There really is no other baseline. It's damaging and outright delusional to compare yourself to the "perfect you" that always bought at the exact bottom and sold at the exact top. That you does not exist. It's a damaging fantasy that always leads to you beating yourself up about not making the most optimal decision at each and every turn. Cryptos can quickly lose its fun if you think along those lines.
Are you in profit (as in cashed out your initial investment + profits in fiat)? Then you're winning - you're doing better than the other you that didn't bother with cryptos. Congratulations. You should extinguish any regret, and actually feel contentment at your achievement. Forget the "what ifs?" - you made a decision that has made you better off financially and you've learned a fair amount along the way.
Are you holding an unrealised loss? Then know that it's unrealised and while that can be stressful, you're doing well to hold on and you can be proud that you haven't sold yet. It won't fix the regret so easily, but you have the hope your unrealised loss can turn into a realised profit.
Are you actually making a realised loss in cryptos? Of course, this is the hardest situation of all. All you can do is see it as a lesson you paid for. Nothing is without value, and you will have learned something along the way. You gave something a try, and financially it didn't work out. You may not be out of the game, so you could be in profit in a few days or weeks' time. Or maybe you've just had enough. Fair play. Know that you're actually in a big group of people. Lots of people have faced your situation and come out the other side OK. I lost a fair amount of money in Forex a few years ago. I felt crap for a while, then I stopped feeling crap. Luckily, life moves on. Actually, without that experience with Forex, I doubt I would have found any interest in cryptos - and I have profited from cryptos much more than my Forex losses - so there is that. Plus, cryptos are a LOT more fun than Forex.
I know that everything above is purely based on financial regret, and the counterargument is that "there's more to cryptos than just making a profit" - but when it comes to regret, it's almost always about money.
A gain is a gain no matter how small it may be. Better to gain something than to lose something. Learn how to be contented of how much you gained and do away with greed.