The crash will teach alot of people a bitter lesson and they will learn from it,
they will learn the following
1. Never to love a coin
2. Never to be greedy
3. To cashout on profit always
4. To stop following hype
5. To know that what goes up must come down etc
Smart people can master everything from the list you listed on their own. Before investing you need to evaluate all the risks. This is what helps then not to regret the loss.
I think sometimes it is even hard for the smart ones and thats why nobody is perfect
You can have the correct information and still fall short
Which is why ah investor cannot relent