I guess everyone has, it's a norm if you spend some time in the altcoins market. Most times why you can't back out now is because you have invested some much time and effort including capital into believing in that project but the market isn't been in your favor. I remember buying a project ones doing the whole Defi hype few months back probably last year but can't remember.
Initially the coin was doing so well then it began dropping. I could sell out but kept trading my already invested capital with the goal of achieve more tokens. I was able to trade and increase my holdings from 5,000 token to around 10k plus tokens. Note this wasn't the dollar value. The dollars value however was steadily declining but I couldn't stop hoping it'll recover and kept trading for more token.
When the defi projects started recovering, I did make back my initial invested capital, all because I now had more tokens than I previously owned and didn't have to wait for the token to go back to its previous high before I could make profit. I guess it'll just me been lucky (prepared), now the token has gone back down.