Even if you are gambling only for fun there will always be an inner desire and wish to make money out of it so I don't think that people gamble only for fun as their main intention is to make good amount of money in quick time which is not possible with any other method.
That's why I don't believe in those gamblers saying it's ok to lose because they are just gambling for fun. Even that is a spare money and can afford to lose, it's impossible they will not aim for the profit and just for fun.
People gambled to profit and "to expect" profit. Who else doesn't want in the first place? No way for every session, whatever gambling games it would be, people will not look into profit.