I kicked myself many times for not doing X or Y at a certain time on the cryptomarket. Yes, it's all hindsight and it is nigh impossible to call the bottoms and peaks on the cryptomarket, but still. Was planning to buy roughly 100 Ethereum in january 2016 but eventually noped out as I thought it wouldn't get traction on the market. Considered to buy $50 worth of XVG (Verge) in january 2017 but forgot about the thing after that ... until I saw its baffling surge in the final months of that year. I could have had the equivalent of hundreds of thousands of USD at this point and it bothered me somewhat for a while, but now my skin has grown thicker in that regard in the sense that I don't care that much about these facts anymore. And indeed, there are still probably oppertunities ahead to make a decent amount of profit on the market. Not selling your crypto seems to be the key!