This seems to be the thread these days...regrets, lost passwords and keys. Funny how people who thought bitcoin was trash have realized how wrong they were. I personally regret selling at $20k
I really don't regret it since I'm probably too young to buy Bitcoin at that year. What I regret the most is having known Bitcoin but doesn't have the capability to buy it, though this is the only regret I have to be honest since I'm fairly satisfied that I've known the existence of cryptocurrency before it become so big.