What I took away from this experience is how the mentality of gamblers can change after a win. The thrill of success often leaves us wanting more and in this case it seemed like my friend was caught in that cycle, as I was feeling before too and he was unable to honor his word probably because he wanted to keep increasing his gains and bet more. It's a reminder that the brain is never truly satisfied when gambling, there's always the desire for more. I believe that friend deserves an advice, but I don’t want to embarrass him myself, is there a good way to talk to him without making him feel that Im indirectly asking him for the money he promised me?