~Snip
They do something ridiculous and embarrassing to their friends because they think they can win the bet even though they know that gambling is not guaranteed to be predicted, they should wait for the guaranteed outcome of the bet before inviting friends to treat or paying for drinks for many people, they end up having to bear two the loss at the same time is the loss of losing the bet and they have to pay the bill for everyone in that casino place.
Every gambler must get used to waiting for the results of bets and if you have won then you are free to use the money for any purpose.
Yes, sometimes expectations do not match reality and that is a consequence that every gambler has to bear. Whenever you win and have withdrawn your balance to your wallet, then invite your friends to have fun, it's much better than promising before winning. But however, this is not obligatory if he says it like this: "If I win, I'll invite you all to party".