The fear of losing money will cause regret when you win a bet. In my opinion, it is just an illusion that crosses someone's mind because they are unable to bear the loss when they lose. In fact, if he was able to think objectively, winning and losing are part of gambling, maybe this small win would not have happened.
Yes, it's all part of the illusion of gambling.
Casinos create an atmosphere of almost euphoria when you win, even a few cents, and nothing when you lose.
So, people still have this innate fear of losing money, which is stronger than the feeling of winning, but with the help of casinos their minds actually forget about the loss while they are playing.
Of course, when they leave the casino reality kicks in.