Beginner investors will feel regret because it has made them lose the opportunity to get bigger profits, but experienced investors are used to this so there will be no regrets because the price of Bitcoin will continue to move up and down and you can always take advantage of this, buying when it goes down and selling it when prices rise, and also if the 4-year cycle repeats itself then those who have sold it can wait for that period to repeat itself and before it happens continue to buy and study the market so that they will have the opportunity to get more profit than before