I don’t know what gives some people the confidence to an extend they will borrow money to gamble. As for me, I can't bring myself to borrow money for gambling, even if I'm expecting money from somewhere. I will never borrow money just to gamble.But from the story you shared, if I viewed your friend as a gambling addict, that could explain why he decided to borrow money to gamble. He likely had some belief that even though he was borrowing, he would still win and pay it back. That might be the reason he’s blaming you as he feels you’re the one who should’ve lent him the money without interest.One thing about addicted gamblers is that they always have hope that, if they gamble more, they’ll get lucky and win. But that’s a very wrong idea. My advice to everyone is: always gamble with what you can afford to lose.