There is a moment that every gambler regrets. I am sure that poker players have especially many such stories, because this is the kind of gambling where not everything depends on luck, but also partly the outcome of the game depends on the poker player himself. For example, when all the cards on the table are opened in a one-on-one game after an all-in and the one who had a good combination of cards in his hands loses.
I have seen this even at international championships in Vegas and it is always a show. But the one who could not win will then remember this for years and regret it.