Of course, the feeling of regret is so deep that when the gambler has lost a lot of money due to their bad behavior, they will think too deeply and the consequence is that if they are unable to withstand the burden of these thoughts, they will experience severe depression.It is true that if a gambler uses gambling games just for entertainment then he will get pleasure and enjoy every game he plays because he only uses gambling when he needs it, not to make money in addition, money might be played excessively.
It's true that if you gamble only for entertainment you won't have regrets of losing money because you're not gambling to make money but for entertainment. If you lose money from gambling, you shouldn't be feeling regrets as you are the one that use that amount for staking and you should have already known the risk that come from staking money when gambling. You're either going to lose the money or you win money therefore every money that you use in gambling is to be considered lost already so you don't feel regrets when you lose it. Your gambling strategy should have the law that you'll always use money that you can forget if you lose them to gambling and you'll not be gambling with borrowed money or money that isn't yours.
It is only when you are not using money to gamble that you will not feel the impact or regret but if you use money to gamble even it is for entertainment purpose and you loss, it will be painful because if you win you will be happy for the win so the same thing to the losing side of the game. And I don't think entertainment is for gambling but it is for game for fun. Gambling is for gain and profit but game is for entertainment and fun. And there is no risk in game but there is risk in gambling. And as I said before, the strategy that one in one game might not for another and might not for another person. So all what we have to do is to know the strategy that is good for each Casino you want to play with and use it. And as you said it is not nice to use borrowed money to gamble.